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Graphs/156326: graph the inequality
2x+5y>5




1 solutions

Answer 115133 by jim_thompson5910(28595) About Me  on 2008-09-11 08:08:27 (Show Source):
You can put this solution on YOUR website!
2x%2B5y%3E5 Start with the given inequality.


5y%3E5-2x Subtract 2x from both sides.


y%3E%285-2x%29%2F%285%29 Divide both sides by 5 to isolate y.


y%3E%285-2x%29%2F%285%29 Subtract x from both sides.


y%3E%28-2x%2B5%29%2F%285%29 Rearrange the terms.


y%3E%28-2x%29%2F%285%29%2B%285%29%2F%285%29 Break up the fraction.


y%3E-%282%2F5%29x%2B1 Reduce


So in order to graph 2x%2B5y%3E5, we need to graph y%3E-%282%2F5%29x%2B1. But first, we must graph the equation y=-%282%2F5%29x%2B1

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C-%282%2F5%29x%2B1%29


Now plug in the test point (0,0) into y%3E-%282%2F5%29x%2B1


y%3E-%282%2F5%29x%2B1


0%3E-%282%2F5%290%2B1


0%3E1


Since the inequality is false, this means that we shade the entire region that does NOT contain (0,0). So this means that we shade everything above the line

Graph of y%3E-%282%2F5%29x%2B1 where the boundary (which should be a dotted line) is the equation y=-%282%2F5%29x%2B1 and the shaded region is in green.


Polynomials-and-rational-expressions/156339: 5. How do I complete this using factoring? Thank you.

x^2 + 6x + 5.
1 solutions

Answer 115130 by jim_thompson5910(28595) About Me  on 2008-09-11 07:59:58 (Show Source):
You can put this solution on YOUR website!

Looking at the expression x%5E2%2B6x%2B5, we can see that the first coefficient is 1, the second coefficient is 6, and the last term is 5.


Now multiply the first coefficient 1 by the last term 5 to get %281%29%285%29=5.


Now the question is: what two whole numbers multiply to 5 (the previous product) and add to the second coefficient 6?


To find these two numbers, we need to list all of the factors of 5 (the previous product).


Factors of 5:
1,5
-1,-5


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to 5.
1*5
(-1)*(-5)

Now let's add up each pair of factors to see if one pair adds to the middle coefficient 6:


First NumberSecond NumberSum
151+5=6
-1-5-1+(-5)=-6



From the table, we can see that the two numbers 1 and 5 add to 6 (the middle coefficient).


So the two numbers 1 and 5 both multiply to 5 and add to 6


Now replace the middle term 6x with x%2B5x. Remember, 1 and 5 add to 6. So this shows us that x%2B5x=6x.


x%5E2%2Bhighlight%28x%2B5x%29%2B5 Replace the second term 6x with x%2B5x.


%28x%5E2%2Bx%29%2B%285x%2B5%29 Group the terms into two pairs.


x%28x%2B1%29%2B%285x%2B5%29 Factor out the GCF x from the first group.


x%28x%2B1%29%2B5%28x%2B1%29 Factor out 5 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%28x%2B5%29%28x%2B1%29 Combine like terms. Or factor out the common term x%2B1

---------------------------------------------


Answer:


So x%5E2%2B6x%2B5 factors to %28x%2B5%29%28x%2B1%29.


Note: you can check the answer by FOILing %28x%2B5%29%28x%2B1%29 to get x%5E2%2B6x%2B5 or by graphing the original expression and the answer (the two graphs should be identical).


Polynomials-and-rational-expressions/156342: 8. Factoring is very hard for me. How do I complete this one?
15x^2 + 7x - 2
thank you for your help.
1 solutions

Answer 115129 by jim_thompson5910(28595) About Me  on 2008-09-11 07:58:38 (Show Source):
You can put this solution on YOUR website!

Looking at the expression 15x%5E2%2B7x-2, we can see that the first coefficient is 15, the second coefficient is 7, and the last term is -2.


Now multiply the first coefficient 15 by the last term -2 to get %2815%29%28-2%29=-30.


Now the question is: what two whole numbers multiply to -30 (the previous product) and add to the second coefficient 7?


To find these two numbers, we need to list all of the factors of -30 (the previous product).


Factors of -30:
1,2,3,5,6,10,15,30
-1,-2,-3,-5,-6,-10,-15,-30


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to -30.
1*(-30)
2*(-15)
3*(-10)
5*(-6)
(-1)*(30)
(-2)*(15)
(-3)*(10)
(-5)*(6)

Now let's add up each pair of factors to see if one pair adds to the middle coefficient 7:


First NumberSecond NumberSum
1-301+(-30)=-29
2-152+(-15)=-13
3-103+(-10)=-7
5-65+(-6)=-1
-130-1+30=29
-215-2+15=13
-310-3+10=7
-56-5+6=1



From the table, we can see that the two numbers -3 and 10 add to 7 (the middle coefficient).


So the two numbers -3 and 10 both multiply to -30 and add to 7


Now replace the middle term 7x with -3x%2B10x. Remember, -3 and 10 add to 7. So this shows us that -3x%2B10x=7x.


15x%5E2%2Bhighlight%28-3x%2B10x%29-2 Replace the second term 7x with -3x%2B10x.


%2815x%5E2-3x%29%2B%2810x-2%29 Group the terms into two pairs.


3x%285x-1%29%2B%2810x-2%29 Factor out the GCF 3x from the first group.


3x%285x-1%29%2B2%285x-1%29 Factor out 2 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%283x%2B2%29%285x-1%29 Combine like terms. Or factor out the common term 5x-1

---------------------------------------------


Answer:


So 15x%5E2%2B7x-2 factors to %283x%2B2%29%285x-1%29.


Note: you can check the answer by FOILing %283x%2B2%29%285x-1%29 to get 15x%5E2%2B7x-2 or by graphing the original expression and the answer (the two graphs should be identical).


Polynomials-and-rational-expressions/156340: 6. How do I complete this using factoring? I appreciate the help.

8x^2 - 22x - 21
1 solutions

Answer 115128 by jim_thompson5910(28595) About Me  on 2008-09-11 07:58:00 (Show Source):
You can put this solution on YOUR website!

Looking at the expression 8x%5E2-22x-21, we can see that the first coefficient is 8, the second coefficient is -22, and the last term is -21.


Now multiply the first coefficient 8 by the last term -21 to get %288%29%28-21%29=-168.


Now the question is: what two whole numbers multiply to -168 (the previous product) and add to the second coefficient -22?


To find these two numbers, we need to list all of the factors of -168 (the previous product).


Factors of -168:
1,2,3,4,6,7,8,12,14,21,24,28,42,56,84,168
-1,-2,-3,-4,-6,-7,-8,-12,-14,-21,-24,-28,-42,-56,-84,-168


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to -168.
1*(-168)
2*(-84)
3*(-56)
4*(-42)
6*(-28)
7*(-24)
8*(-21)
12*(-14)
(-1)*(168)
(-2)*(84)
(-3)*(56)
(-4)*(42)
(-6)*(28)
(-7)*(24)
(-8)*(21)
(-12)*(14)

Now let's add up each pair of factors to see if one pair adds to the middle coefficient -22:


First NumberSecond NumberSum
1-1681+(-168)=-167
2-842+(-84)=-82
3-563+(-56)=-53
4-424+(-42)=-38
6-286+(-28)=-22
7-247+(-24)=-17
8-218+(-21)=-13
12-1412+(-14)=-2
-1168-1+168=167
-284-2+84=82
-356-3+56=53
-442-4+42=38
-628-6+28=22
-724-7+24=17
-821-8+21=13
-1214-12+14=2



From the table, we can see that the two numbers 6 and -28 add to -22 (the middle coefficient).


So the two numbers 6 and -28 both multiply to -168 and add to -22


Now replace the middle term -22x with 6x-28x. Remember, 6 and -28 add to -22. So this shows us that 6x-28x=-22x.


8x%5E2%2Bhighlight%286x-28x%29-21 Replace the second term -22x with 6x-28x.


%288x%5E2%2B6x%29%2B%28-28x-21%29 Group the terms into two pairs.


2x%284x%2B3%29%2B%28-28x-21%29 Factor out the GCF 2x from the first group.


2x%284x%2B3%29-7%284x%2B3%29 Factor out 7 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%282x-7%29%284x%2B3%29 Combine like terms. Or factor out the common term 4x%2B3

---------------------------------------------


Answer:


So 8x%5E2-22x-21 factors to %282x-7%29%284x%2B3%29.


Note: you can check the answer by FOILing %282x-7%29%284x%2B3%29 to get 8x%5E2-22x-21 or by graphing the original expression and the answer (the two graphs should be identical).


Graphs/156298: Evaluate the functions for the values of x given as 1, 2, 4, 8, and 16. Describe the differences in the rate at which each function changes with increasing values of x.


5. f(x) = ln x




1 solutions

Answer 115099 by jim_thompson5910(28595) About Me  on 2008-09-10 21:11:48 (Show Source):
You can put this solution on YOUR website!

# 5

Note: ln(x) also looks like LN(x) (to pronounce it, simply read off the letters "L" "N")

This is the natural log of x. So it is a logarithmic function.

Let's find the y value when x=1


y=ln%28x%29 Start with the given equation.


y=ln%281%29 Plug in x=1.


y=0 Take the natural log of 1 to get 0


So when x=1, y=0.


----------------------------


Let's find the y value when x=2


y=ln%28x%29 Start with the given equation.


y=ln%282%29 Plug in x=2.


y=0.693 Take the natural log of 2 to get 0.693


So when x=2, y=0.693.



----------------------------


Let's find the y value when x=4


y=ln%28x%29 Start with the given equation.


y=ln%284%29 Plug in x=4.


y=1.386 Take the natural log of 4 to get 1.386


So when x=4, y=1.386.

-------------------------------

Let's find the y value when x=8


y=ln%28x%29 Start with the given equation.


y=ln%288%29 Plug in x=8.


y=2.079 Take the natural log of 8 to get 2.079


So when x=8, y=2.079.


-------------------------------------


Let's find the y value when x=16


y=ln%28x%29 Start with the given equation.


y=ln%2816%29 Plug in x=16.


y=2.773 Take the natural log of 16 to get 2.773


So when x=16, y=2.773.


Now let's make a table of the values we just found.



Table of Values:


xy
10
20.693
41.386
82.079
162.773


Since the natural log function is logarithmic, this means that the growth is logarithmic. This growth rate is slower than linear growth rate and is the slowest growth rate than all of the growth rates.

===========================================================

So here's the order of function's growth from smallest growth rate to largest growth rate

y=ln%28x%29, y=5x-3, y=x%5E2-3x%2B2, and y=2x%5E3%2B7x%5E2-x-1, and y=10%5Ex


Graphs/156297: Evaluate the functions for the values of x given as 1, 2, 4, 8, and 16. Describe the differences in the rate at which each function changes with increasing values of x.

4. f(x) = 10^x



1 solutions

Answer 115098 by jim_thompson5910(28595) About Me  on 2008-09-10 21:09:56 (Show Source):
You can put this solution on YOUR website!
# 4




Let's find the function value when x=1:


y=10%5Ex Start with the given equation.


y=10%5E%281%29 Plug in x=1.


y=10 Raise 10 to the first power to get 10


So if x=1, then y=10.

-------------

Let's find the function value when x=2:


y=10%5Ex Start with the given equation.


y=10%5E%282%29 Plug in x=2.


y=100 Raise 10 to the second power to get 100


So if x=2, then y=100.

-------------

Let's find the function value when x=4:


y=10%5Ex Start with the given equation.


y=10%5E%284%29 Plug in x=4.


y=10000 Raise 10 to the 4th power to get 10,000



So if x=4, then y=10000.

-------------

Let's find the function value when x=8:


y=10%5Ex Start with the given equation.


y=10%5E%288%29 Plug in x=8.


y=100000000 Raise 10 to the 8th power to get 100,000,000


So if x=8, then y=100000000.

-------------

Let's find the function value when x=16:


y=10%5Ex Start with the given equation.


y=10%5E%2816%29 Plug in x=16.


y=1%2A10%5E16 Raise 10 to the 16th power to get 1%2A10%5E16 (this is a 1 followed by 16 zeros)



So if x=16, then y=1%2A10%5E16.

-------------

Now let's make a table of the values we just found.


Table of Values:


xy
110
2100
410,000
8100,000,000
161*10^16



Since we are dealing with an exponential function, this means that the function undergoes exponential growth. This is the fastest of all of the growth rates in this group.


Graphs/156295: Evaluate the functions for the values of x given as 1, 2, 4, 8, and 16. Describe the differences in the rate at which each function changes with increasing values of x.

3. f(x) = 2x3 + 7x2 - x - 1


1 solutions

Answer 115097 by jim_thompson5910(28595) About Me  on 2008-09-10 21:02:33 (Show Source):
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# 3

Let's find the function value when x=1:


y=2x%5E3%2B7x%5E2-x-1 Start with the given equation.


y=2%281%29%5E3%2B7%281%29%5E2-1-1 Plug in x=1.


y=2%281%29%2B7%281%29%5E2-1-1 Cube 1 to get 1.


y=2%281%29%2B7%281%29-1-1 Square 1 to get 1.


y=2%2B7%281%29-1-1 Multiply 2 and 1 to get 2.


y=2%2B7-1-1 Multiply 7 and 1 to get 7.


y=7 Combine like terms.


So if x=1, then y=7.

-------------

Let's find the function value when x=2:


y=2x%5E3%2B7x%5E2-x-1 Start with the given equation.


y=2%282%29%5E3%2B7%282%29%5E2-2-1 Plug in x=2.


y=2%288%29%2B7%282%29%5E2-2-1 Cube 2 to get 8.


y=2%288%29%2B7%284%29-2-1 Square 2 to get 4.


y=16%2B7%284%29-2-1 Multiply 2 and 8 to get 16.


y=16%2B28-2-1 Multiply 7 and 4 to get 28.


y=41 Combine like terms.


So if x=2, then y=41.

-------------

Let's find the function value when x=4:


y=2x%5E3%2B7x%5E2-x-1 Start with the given equation.


y=2%284%29%5E3%2B7%284%29%5E2-4-1 Plug in x=4.


y=2%2864%29%2B7%284%29%5E2-4-1 Cube 4 to get 64.


y=2%2864%29%2B7%2816%29-4-1 Square 4 to get 16.


y=128%2B7%2816%29-4-1 Multiply 2 and 64 to get 128.


y=128%2B112-4-1 Multiply 7 and 16 to get 112.


y=235 Combine like terms.


So if x=4, then y=235.

-------------

Let's find the function value when x=8:


y=2x%5E3%2B7x%5E2-x-1 Start with the given equation.


y=2%288%29%5E3%2B7%288%29%5E2-8-1 Plug in x=8.


y=2%28512%29%2B7%288%29%5E2-8-1 Cube 8 to get 512.


y=2%28512%29%2B7%2864%29-8-1 Square 8 to get 64.


y=1024%2B7%2864%29-8-1 Multiply 2 and 512 to get 1024.


y=1024%2B448-8-1 Multiply 7 and 64 to get 448.


y=1463 Combine like terms.


So if x=8, then y=1463.

-------------

Let's find the function value when x=16:


y=2x%5E3%2B7x%5E2-x-1 Start with the given equation.


y=2%2816%29%5E3%2B7%2816%29%5E2-16-1 Plug in x=16.


y=2%284096%29%2B7%2816%29%5E2-16-1 Cube 16 to get 4096.


y=2%284096%29%2B7%28256%29-16-1 Square 16 to get 256.


y=8192%2B7%28256%29-16-1 Multiply 2 and 4096 to get 8192.


y=8192%2B1792-16-1 Multiply 7 and 256 to get 1792.


y=9967 Combine like terms.


So if x=16, then y=9967.

-------------

Now let's make a table of the values we just found.



Table of Values:


xy
17
241
4235
81463
169967


Since this polynomial is a cubic, this tells us that the rate of growth is cubic growth. This growth rate is larger than quadratic growth.


Graphs/156294: Evaluate the functions for the values of x given as 1, 2, 4, 8, and 16. Describe the differences in the rate at which each function changes with increasing values of x.
2. f(x) = x2 - 3x + 2

1 solutions

Answer 115096 by jim_thompson5910(28595) About Me  on 2008-09-10 21:01:06 (Show Source):
You can put this solution on YOUR website!
# 2


Let's find the function value when x=1:


y=x%5E2-3x%2B2 Start with the given equation.


y=%281%29%5E2-3%281%29%2B2 Plug in x=1.


y=1%281%29-3%281%29%2B2 Square 1 to get 1.


y=1-3%281%29%2B2 Multiply 1 and 1 to get 1.


y=1-3%2B2 Multiply -3 and 1 to get -3.


y=0 Combine like terms.


So if x=1, then y=0.

-------------

Let's find the function value when x=2:


y=x%5E2-3x%2B2 Start with the given equation.


y=%282%29%5E2-3%282%29%2B2 Plug in x=2.


y=1%284%29-3%282%29%2B2 Square 2 to get 4.


y=4-3%282%29%2B2 Multiply 1 and 4 to get 4.


y=4-6%2B2 Multiply -3 and 2 to get -6.


y=0 Combine like terms.


So if x=2, then y=0.

-------------

Let's find the function value when x=4:


y=x%5E2-3x%2B2 Start with the given equation.


y=%284%29%5E2-3%284%29%2B2 Plug in x=4.


y=1%2816%29-3%284%29%2B2 Square 4 to get 16.


y=16-3%284%29%2B2 Multiply 1 and 16 to get 16.


y=16-12%2B2 Multiply -3 and 4 to get -12.


y=6 Combine like terms.


So if x=4, then y=6.

-------------

Let's find the function value when x=8:


y=x%5E2-3x%2B2 Start with the given equation.


y=%288%29%5E2-3%288%29%2B2 Plug in x=8.


y=1%2864%29-3%288%29%2B2 Square 8 to get 64.


y=64-3%288%29%2B2 Multiply 1 and 64 to get 64.


y=64-24%2B2 Multiply -3 and 8 to get -24.


y=42 Combine like terms.


So if x=8, then y=42.

-------------

Let's find the function value when x=16:


y=x%5E2-3x%2B2 Start with the given equation.


y=%2816%29%5E2-3%2816%29%2B2 Plug in x=16.


y=1%28256%29-3%2816%29%2B2 Square 16 to get 256.


y=256-3%2816%29%2B2 Multiply 1 and 256 to get 256.


y=256-48%2B2 Multiply -3 and 16 to get -48.


y=210 Combine like terms.


So if x=16, then y=210.

-------------

Now let's make a table of the values we just found.





Jump to Top of Page

Table of Values:


xy
10
20
46
842
16210



Because the function is a quadratic, this means that the polynomial undergoes quadratic growth. This is faster than linear growth.


Graphs/156293: Evaluate the functions for the values of x given as 1, 2, 4, 8, and 16. Describe the differences in the rate at which each function changes with increasing values of x.
1. f(x) = 5x - 3

1 solutions

Answer 115095 by jim_thompson5910(28595) About Me  on 2008-09-10 20:59:27 (Show Source):
You can put this solution on YOUR website!
# 1

Let's find the function value when x=1:


y=5x-3 Start with the given equation.


y=5%281%29-3 Plug in x=1.


y=5-3 Multiply 5 and 1 to get 5.


y=2 Combine like terms.


So if x=1, then y=2.

-------------

Let's find the function value when x=2:


y=5x-3 Start with the given equation.


y=5%282%29-3 Plug in x=2.


y=10-3 Multiply 5 and 2 to get 10.


y=7 Combine like terms.


So if x=2, then y=7.

-------------

Let's find the function value when x=4:


y=5x-3 Start with the given equation.


y=5%284%29-3 Plug in x=4.


y=20-3 Multiply 5 and 4 to get 20.


y=17 Combine like terms.


So if x=4, then y=17.

-------------

Let's find the function value when x=8:


y=5x-3 Start with the given equation.


y=5%288%29-3 Plug in x=8.


y=40-3 Multiply 5 and 8 to get 40.


y=37 Combine like terms.


So if x=8, then y=37.

-------------

Let's find the function value when x=16:


y=5x-3 Start with the given equation.


y=5%2816%29-3 Plug in x=16.


y=80-3 Multiply 5 and 16 to get 80.


y=77 Combine like terms.


So if x=16, then y=77.

-------------

Now let's make a table of the values we just found.





Jump to Top of Page

Table of Values:


xy
12
27
417
837
1677



Since this is a linear equation, this means that the equation experiences linear growth. This is considered moderate growth.


Graphs/156282: 3. Plot the graph of the above equations formed in question 2, and post your response to the discussion forum.

1 solutions

Answer 115092 by jim_thompson5910(28595) About Me  on 2008-09-10 20:27:47 (Show Source):
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Here are the graphs to question 2

a)

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C5x%2B2%29 Graph of 5x%2B2=0

b)

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C%28-x%2B7-2%29%2F3%29 Graph of 3y-2=-x%2B7

c)

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C3x%5E2%2B2x%2B5%29 Graph of 3x%5E2%2B2x%2B5=0


c)

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C7x%5E2-5x-3%29 Graph of 7x%5E2-5x-3

d)

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C3%5Ex%29 Graph of f%28x%29=3%5Ex

e)

graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Clog%284%2C%28x%29%29%29 Graph of f%28x%29=log%284%2C%28x%29%29


Graphs/156280: 2. Form each of the following:
• A linear equation in one variable
• A linear equation in two variables
• A quadratic equation
• A polynomial of three terms
• An exponential function
• A logarithmic function

1 solutions

Answer 115091 by jim_thompson5910(28595) About Me  on 2008-09-10 20:27:00 (Show Source):
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a) A linear equation in one variable : 5x%2B2=0

b) A linear equation in two variables : 3y-2=-x%2B7

c) Quadratic equation: 3x%5E2%2B2x-3=0

d) A polynomial of three terms: 7x%5E2-5x%2B12

e) Exponential Function: f%28x%29=3%5Ex

f) Logarithmic Function: f%28x%29=log%284%2C%28x%29%29


Graphs/156278: 1. Give an example of an exponential function. Convert this exponential function to a logarithmic function. Plot the graph of both the functions and post to the discussion forum. Discuss these functions and their graphs with your classmates
1 solutions

Answer 115088 by jim_thompson5910(28595) About Me  on 2008-09-10 20:24:33 (Show Source):
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Example of an Exponential function: f%28x%29=3%5Ex

Now convert the Exponential function to a Logarithmic function using the property b%5Ex=y <====> log%28b%2C%28y%29%29=x:

g%28x%29=log%283%2C%28x%29%29


Now let's graph the exponential function f%28x%29=3%5Ex (red) and the logarithmic function g%28x%29=log%283%2C%28x%29%29 (green)


+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+3%5Ex%2C+log%283%2C%28x%29%29%29+


Notice how the logarithmic function is simply a reflection of the exponential function over the line y=x


Inequalities/156129: 2(5y-6) > (3y+6)
-
Solution is {y|y __ __ }
1 solutions

Answer 115041 by jim_thompson5910(28595) About Me  on 2008-09-10 14:17:11 (Show Source):
You can put this solution on YOUR website!
2%285y-6%29%3E=3y%2B6 Start with the given inequality.


10y-12%3E=3y%2B6 Distribute.


10y%3E=3y%2B6%2B12 Add 12 to both sides.


10y-3y%3E=6%2B12 Subtract 3y from both sides.


7y%3E=6%2B12 Combine like terms on the left side.


7y%3E=18 Combine like terms on the right side.


y%3E=%2818%29%2F%287%29 Divide both sides by 7 to isolate y.


----------------------------------------------------------------------

Answer:

So the answer is y%3E=18%2F7


Which approximates to y%3E=2.571



So the solution set is


Also, the answer in interval notation is [)


Finally, here's the graph of the solution set



Note: the endpoint is an closed circle


Linear-systems/156160: 11+g+4-9=30
11+4m=4m+8
6a=2(4-a)
20=-5/4a
2(h-3)=5+13
how to solve it?
1 solutions

Answer 115037 by jim_thompson5910(28595) About Me  on 2008-09-10 14:08:41 (Show Source):
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I'll do the first three to get you started

# 1



11%2Bg%2B4-9=30 Start with the given equation.


g%2B6=30 Combine like terms on the left side.


g=30-6 Subtract 6 from both sides.


g=24 Combine like terms on the right side.


----------------------------------------------------------------------

Answer:

So the answer is g=24






# 2



11%2B4m=4m%2B8 Start with the given equation.


4m=4m%2B8-11 Subtract 11 from both sides.


4m-4m=8-11 Subtract 4m from both sides.


0m=8-11 Combine like terms on the left side.


0m=-3 Combine like terms on the right side.


0=-3 Simplify.


Since this equation is never true for any m value, this means that there are no solutions. So the equation is inconsistent.






# 3



6a=2%284-a%29 Start with the given equation.


6a=8-2a Distribute.


6a%2B2a=8 Add 2a to both sides.


8a=8 Combine like terms on the left side.


a=%288%29%2F%288%29 Divide both sides by 8 to isolate a.


a=1 Reduce.


----------------------------------------------------------------------

Answer:

So the answer is a=1


Expressions-with-variables/156164: simplify 6-a+2ac+5c-3ca
1 solutions

Answer 115034 by jim_thompson5910(28595) About Me  on 2008-09-10 14:04:19 (Show Source):
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6-a%2B2ac%2B5c-3ca Start with the given expression


%285c%29%2B%28-a%29%2B%282ac-3ac%29%2B%286%29 Group the common terms. Note ac=ca


5c-a-ac%2B6 Combine like terms


So 6-a%2B2ac%2B5c-3ca=5c-a-ac%2B6


Geometry_Word_Problems/156165: Hello;
I was wondering if you could help me with the following problem;
What is the equation of the line that contains the points with (x,y) coordinates (-3,7) and (5,-1)?
Sorry, I don't have book's name or the number.
1 solutions

Answer 115033 by jim_thompson5910(28595) About Me  on 2008-09-10 13:54:42 (Show Source):
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First let's find the slope of the line through the points and


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%28-1-7%29%2F%285--3%29 Plug in y%5B2%5D=-1, y%5B1%5D=7, x%5B2%5D=5, and x%5B1%5D=-3


m=%28-8%29%2F%285--3%29 Subtract 7 from -1 to get -8


m=%28-8%29%2F%288%29 Subtract -3 from 5 to get 8


m=-1 Reduce


So the slope of the line that goes through the points and is m=-1


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y-7=-1%28x--3%29 Plug in m=-1, x%5B1%5D=-3, and y%5B1%5D=7


y-7=-1%28x%2B3%29 Rewrite x--3 as x%2B3


y-7=-1x%2B-1%283%29 Distribute


y-7=-1x-3 Multiply


y=-1x-3%2B7 Add 7 to both sides.


y=-1x%2B4 Combine like terms.


y=-x%2B4 Simplify


So the equation that goes through the points and is y=-x%2B4


Notice how the graph of y=-x%2B4 goes through the points and . So this visually verifies our answer.
Graph of y=-x%2B4 through the points and


Polynomials-and-rational-expressions/156166: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM:
If f(g(x)) = g(f(x)) = x, then whay can we say about f(x) and g(x)?
a. they are functional inverses of each other
b. f(x) = g(x)
c. f(x) = g(x) = x
d. nothing can be said about f(x) and g(x)

1 solutions

Answer 115031 by jim_thompson5910(28595) About Me  on 2008-09-10 13:53:52 (Show Source):
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Remember, if f(x) and g(x) are inverses of one another, then we can say that f(g(x))=x and g(f(x))=x. So this means that the answer is a) they are functional inverses of each other


Note: we know nothing about f(x) and g(x). So we cannot just blindly assume that f(x)=g(x) or f(x)=g(x)=x without some evidence. So this rules our choices b) and c).


Functions/156168: I have one more problem that hopefully you'll be able to help me;
If f(4)=0 and f(6) =6, which of the following could represent f(x)?
A. 2/3x-4
B. x+2
C. x-4
D. 3/2x+6
E. 3x-12
1 solutions

Answer 115030 by jim_thompson5910(28595) About Me  on 2008-09-10 13:50:32 (Show Source):
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The statement f%284%29=0 tells us that if x=4, then y=0. So the point (4,0) is on the line. Also, the statement f%286%29+=6 tells us that if x=6, then y=6. So the point (6,6) is also on the line.


So let's find the equation of the line that goes through the two points (4,0) and (6,6)



To do that, we first need to find the slope of the line through the points and


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%286-0%29%2F%286-4%29 Plug in y%5B2%5D=6, y%5B1%5D=0, x%5B2%5D=6, and x%5B1%5D=4


m=%286%29%2F%286-4%29 Subtract 0 from 6 to get 6


m=%286%29%2F%282%29 Subtract 4 from 6 to get 2


m=3 Reduce


So the slope of the line that goes through the points and is m=3


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y-0=3%28x-4%29 Plug in m=3, x%5B1%5D=4, and y%5B1%5D=0


y-0=3x%2B3%28-4%29 Distribute


y-0=3x-12 Multiply


y=3x-12%2B0 Add 0 to both sides.


y=3x-12 Combine like terms.


y=3x-12 Simplify


So the equation that goes through the points and is y=3x-12


In function notation, the answer is f%28x%29=3x-12

Notice how f%284%29=3%284%29-12=12-12=0 and f%286%29=3%286%29-12=18-12=6. So this also verifies our answer.



Also, notice how the graph of y=3x-12 goes through the points and . So this visually verifies our answer.
Graph of y=3x-12 through the points and



Quadratic-relations-and-conic-sections/156163: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM:
Complete the square and write the equation in standard form. Then give the center and radius of the circle. x^2 + y^2 - 2x - 4y -4 = 0.

1 solutions

Answer 115029 by jim_thompson5910(28595) About Me  on 2008-09-10 13:39:08 (Show Source):
You can put this solution on YOUR website!
x%5E2+%2B+y%5E2+-+2x+-+4y+-4+=+0 Start with the given equation


x%5E2-+2x+%2B+y%5E2++-+4y+-4+=+0 Rearrange the terms (place the "x" and "y" terms together)


x%5E2-+2x+%2Bhighlight%281%29+%2B+y%5E2++-+4y+-4+=+highlight%281%29 Take half of the "x" coefficient and square it to get %28%28-2%29%2F2%29%5E2=%28-1%29%5E2=1. Add this to both sides (note: add the one right after the -2x)



x%5E2-+2x+%2B1+%2B+y%5E2++-+4y+%2Bhighlight%284%29+-4+=+1%2Bhighlight%284%29 Take half of the "y" coefficient and square it to get %28%28-4%29%2F2%29%5E2=%28-2%29%5E2=4. Add this to both sides (note: add the four right after the -4y)


x%5E2-+2x+%2B1+%2B+y%5E2++-+4y+%2B4+-4+=+5 Combine like terms on the right side

%28x%5E2-+2x+%2B1+%29%2B+%28y%5E2++-+4y+%2B4+%29-4+=+5 Group the terms into two groups of three terms in each


%28x-1%29%5E2%2B+%28y%5E2++-+4y+%2B4+%29-4+=+5 Factor x%5E2-+2x+%2B1 to get %28x-1%29%5E2


%28x-1%29%5E2%2B+%28y-2%29%5E2-4+=+5 Factor y%5E2++-+4y+%2B4 to get %28y-2%29%5E2


%28x-1%29%5E2%2B+%28y-2%29%5E2+=+9 Add 4 to both sides


Now we have an equation in the form of %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2 where h=1, k=2, and r=3. Remember, for the general circle %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2, the center is (h,k) and and the radius is "r"


So for %28x-1%29%5E2%2B+%28y-2%29%5E2+=+9, the center is (1,2) and the radius is 3 units


Polynomials-and-rational-expressions/156161: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM:
What is g(x) = f^-1(x) if f(x) = 1/2 x?
a. g(x) = 0
b. g(x) = -2x
c. g(x) = 1/2x^-1
d. g(x) = 2x
1 solutions

Answer 115028 by jim_thompson5910(28595) About Me  on 2008-09-10 13:30:59 (Show Source):
You can put this solution on YOUR website!
Is the function f%28x%29=%281%2F2%29x ?


f%28x%29=%281%2F2%29x Start with the given expression


y=%281%2F2%29x Replace f%28x%29 with "y"


x=%281%2F2%29y Switch "x" and "y"


2x=y Multiply both sides by 2 to solve for "y"


So after solving for "y", we get y=2x. So the inverse function is


======================================

Or...

Is the function f%28x%29=%281%29%2F%282x%29 ?


f%28x%29=%281%29%2F%282x%29 Start with the given expression


y=%281%29%2F%282x%29 Replace f%28x%29 with "y"


x=%281%29%2F%282y%29 Switch "x" and "y"


2xy=1 Multiply both sides by 2y


y=1%2F%282x%29 Divide both sides by 2x to solve for "y"


So after solving for "y", we get y=1%2F%282x%29. So the inverse function is


Quadratic_Equations/156147: I have a swan that weighs 25 lbs. and is 4 ft. long. Using this equation what is the L in wing span in feet.
Equation: L=2.43*W^0.3326
1 solutions

Answer 115027 by jim_thompson5910(28595) About Me  on 2008-09-10 13:26:39 (Show Source):
You can put this solution on YOUR website!
I think they threw in the fact that the swan "is 4 ft. long" to throw you off (since it's extra info that you don't need)

L=2.43%2AW%5E0.3326 Start with the given equation


L=2.43%2A25%5E0.3326 Plug in W=25


L=2.43%2A2.917 Raise 25 to the 0.3326th power to get 2.917


L=7.08831 Multiply 2.43 and 2.917 to get 7.08831


So the approximate wingspan (we introduced rounding errors) is about 7.09 feet (rounded to the nearest hundredth).


Matrices-and-determiminant/156056: You have been performing Gaussian Elimination, and now you have all of the lower
triangle elements with value 0. What are you ready to do? I think the answer is c, but I want to make sure

a. Nothing, you are done with Gaussian Elimination
b. Start with forwards elimination
c. Start backwards elimination
d. Start over; you are supposed to have all zeroes in the upper triangle
1 solutions

Answer 115025 by jim_thompson5910(28595) About Me  on 2008-09-10 13:21:17 (Show Source):
You can put this solution on YOUR website!
You are correct. You want to end up with a matrix with a diagonal of 1's where every other element (except for the far right column) is zero.


Note: It's not always possible to obtain this since you may have no solutions or an infinite number of solutions.


Expressions-with-variables/156158: Expand 5y{x-2y+3}
1 solutions

Answer 115022 by jim_thompson5910(28595) About Me  on 2008-09-10 13:17:39 (Show Source):


Matrices-and-determiminant/156047: If A is a 3 × 4 matrix, B is a 4 × 12 matrix, and C is a 12 × 2 matrix, then CBA is:
a. 13,824
b. a 3 × 4 × 12 matrix
c. a 3 × 2 matrix
d. none of the above, these matrices do not match up
1 solutions

Answer 115021 by jim_thompson5910(28595) About Me  on 2008-09-10 13:16:41 (Show Source):
You can put this solution on YOUR website!
Notice how B is 4 × 12 and A is 3 × 4

The number of columns in matrix B (12) do NOT equal the number of rows in matrix A (3). So this means that BA is not possible. So the answer choice is d) none of the above, these matrices do not match up


expressions/156007: 5(2m+5)-6

1 solutions

Answer 115020 by jim_thompson5910(28595) About Me  on 2008-09-10 13:13:09 (Show Source):


absolute-value/156156: if x^2+6x+16=(x+a)^2+b for all values of x, find the values of a and b
1 solutions

Answer 115019 by jim_thompson5910(28595) About Me  on 2008-09-10 13:12:27 (Show Source):
You can put this solution on YOUR website!
x%5E2%2B6x%2B16=%28x%2Ba%29%5E2%2Bb Start with the given equation


x%5E2%2B6x%2B16=x%5E2%2B2ax%2Ba%5E2%2Bb FOIL


6x%2B16=2ax%2Ba%5E2%2Bb Subtract x%5E2 from both sides


Notice how the term 2ax is the only term on the right side that has an "x" in it. So this means that 6x=2ax

6x=2ax Start with the given equation


3=a Divide both sides by 2x to isolate "a"


So the first answer is a=3

-------------------------

Looking back at 6x%2B16=2ax%2Ba%5E2%2Bb, the terms a%5E2%2Bb do not have an "x" term in them at all. So this means that 16=a%5E2%2Bb


16=a%5E2%2Bb Start with the given equation


16=3%5E2%2Bb Plug in a=3


16=9%2Bb Square 3 to get 9


7=b Subtract 9 from both sides


So the second answer is b=7


-----------------------------------

Answer:

So the solutions are a=3 and b=7




Check:

x%5E2%2B6x%2B16=%28x%2Ba%29%5E2%2Bb


+x%5E2%2B6x%2B16=%28x%2B3%29%5E2%2B7


+x%5E2%2B6x%2B16=x%5E2%2B6x%2B9%2B7


+x%5E2%2B6x%2B16=x%5E2%2B6x%2B16

0=0 works



absolute-value/156157: if x^2+6x+16=(x+a)^2+b for all values of x, find the values of a and b
1 solutions

Answer 115018 by jim_thompson5910(28595) About Me  on 2008-09-10 13:12:07 (Show Source):
You can put this solution on YOUR website!
x%5E2%2B6x%2B16=%28x%2Ba%29%5E2%2Bb Start with the given equation


x%5E2%2B6x%2B16=x%5E2%2B2ax%2Ba%5E2%2Bb FOIL


6x%2B16=2ax%2Ba%5E2%2Bb Subtract x%5E2 from both sides


Notice how the term 2ax is the only term on the right side that has an "x" in it. So this means that 6x=2ax

6x=2ax Start with the given equation


3=a Divide both sides by 2x to isolate "a"


So the first answer is a=3

-------------------------

Looking back at 6x%2B16=2ax%2Ba%5E2%2Bb, the terms a%5E2%2Bb do not have an "x" term in them at all. So this means that 16=a%5E2%2Bb


16=a%5E2%2Bb Start with the given equation


16=3%5E2%2Bb Plug in a=3


16=9%2Bb Square 3 to get 9


7=b Subtract 9 from both sides


So the second answer is b=7


-----------------------------------

Answer:

So the solutions are a=3 and b=7




Check:

x%5E2%2B6x%2B16=%28x%2Ba%29%5E2%2Bb


+x%5E2%2B6x%2B16=%28x%2B3%29%5E2%2B7


+x%5E2%2B6x%2B16=x%5E2%2B6x%2B9%2B7


+x%5E2%2B6x%2B16=x%5E2%2B6x%2B16

0=0 works



Square-cubic-other-roots/156155: Is 4 or -1 a root of the equation ysquared-3y=4?
1 solutions

Answer 115017 by jim_thompson5910(28595) About Me  on 2008-09-10 13:10:55 (Show Source):
You can put this solution on YOUR website!
y%5E2-3y=4 Start with the given equation


y%5E2-3y-4=0 Subtract 4 from both sides


Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for y:


Starting with the general quadratic


ay%5E2%2Bby%2Bc=0


the general solution using the quadratic equation is:


y+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29




So lets solve y%5E2-3%2Ay-4=0 ( notice a=1, b=-3, and c=-4)





y+=+%28--3+%2B-+sqrt%28+%28-3%29%5E2-4%2A1%2A-4+%29%29%2F%282%2A1%29 Plug in a=1, b=-3, and c=-4




y+=+%283+%2B-+sqrt%28+%28-3%29%5E2-4%2A1%2A-4+%29%29%2F%282%2A1%29 Negate -3 to get 3




y+=+%283+%2B-+sqrt%28+9-4%2A1%2A-4+%29%29%2F%282%2A1%29 Square -3 to get 9 (note: remember when you square -3, you must square the negative as well. This is because %28-3%29%5E2=-3%2A-3=9.)




y+=+%283+%2B-+sqrt%28+9%2B16+%29%29%2F%282%2A1%29 Multiply -4%2A-4%2A1 to get 16




y+=+%283+%2B-+sqrt%28+25+%29%29%2F%282%2A1%29 Combine like terms in the radicand (everything under the square root)




y+=+%283+%2B-+5%29%2F%282%2A1%29 Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




y+=+%283+%2B-+5%29%2F2 Multiply 2 and 1 to get 2


So now the expression breaks down into two parts


y+=+%283+%2B+5%29%2F2 or y+=+%283+-+5%29%2F2


Lets look at the first part:


x=%283+%2B+5%29%2F2


y=8%2F2 Add the terms in the numerator

y=4 Divide


So one answer is

y=4




Now lets look at the second part:


x=%283+-+5%29%2F2


y=-2%2F2 Subtract the terms in the numerator

y=-1 Divide


So another answer is

y=-1


So our solutions are:

y=4 or y=-1





So 4 or -1 is a root of the equation y%5E2-3y=4


Trigonometry-basics/156050: Adding together the first ten natural numbers is an example of a(n):
a. series
b. arithmetic series
c. geometric series
d. power series
1 solutions

Answer 115016 by jim_thompson5910(28595) About Me  on 2008-09-10 13:09:12 (Show Source):
You can put this solution on YOUR website!
Adding together the first ten natural numbers is an example of a(n): b. arithmetic series


An "arithmetic sequence" is simply a sequence where you add a constant number to each term. In this case, you add 1 to each term. An "arithmetic series" is simply the sequence of sums of the arithmetic sequence.


Polynomials-and-rational-expressions/156142: If x^2+6x+16=(x+a)^2+b for all values of x. Find a and b
1 solutions

Answer 115015 by jim_thompson5910(28595) About Me  on 2008-09-10 13:07:14 (Show Source):
You can put this solution on YOUR website!
x%5E2%2B6x%2B16=%28x%2Ba%29%5E2%2Bb Start with the given equation


x%5E2%2B6x%2B16=x%5E2%2B2ax%2Ba%5E2%2Bb FOIL


6x%2B16=2ax%2Ba%5E2%2Bb Subtract x%5E2 from both sides


Notice how the term 2ax is the only term on the right side that has an "x" in it. So this means that 6x=2ax

6x=2ax Start with the given equation


3=a Divide both sides by 2x to isolate "a"


So the first answer is a=3

-------------------------

Looking back at 6x%2B16=2ax%2Ba%5E2%2Bb, the terms a%5E2%2Bb do not have an "x" term in them at all. So this means that 16=a%5E2%2Bb


16=a%5E2%2Bb Start with the given equation


16=3%5E2%2Bb Plug in a=3


16=9%2Bb Square 3 to get 9


7=b Subtract 9 from both sides


So the second answer is b=7



Check:

x%5E2%2B6x%2B16=%28x%2Ba%29%5E2%2Bb}


+x%5E2%2B6x%2B16=%28x%2B3%29%5E2%2B7


+x%5E2%2B6x%2B16=x%5E2%2B6x%2B9%2B7


+x%5E2%2B6x%2B16=x%5E2%2B6x%2B16

0=0 works



Quadratic_Equations/156148: Solve
15x^4-31x^2+10=0
The solution of x= ??
1 solutions

Answer 115014 by jim_thompson5910(28595) About Me  on 2008-09-10 13:01:22 (Show Source):
You can put this solution on YOUR website!
Let z=x%5E2. So z%5E2=%28x%5E2%29%5E2=x%5E4. In short, z%5E2=x%5E4

15x%5E4-31x%5E2%2B10=0 Start with the given equation


15z%5E2-31z%2B10=0 Plug in z=x%5E2 and z%5E2=x%5E4



Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for z:


Starting with the general quadratic


az%5E2%2Bbz%2Bc=0


the general solution using the quadratic equation is:


z+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29




So lets solve 15%2Az%5E2-31%2Az%2B10=0 ( notice a=15, b=-31, and c=10)





z+=+%28--31+%2B-+sqrt%28+%28-31%29%5E2-4%2A15%2A10+%29%29%2F%282%2A15%29 Plug in a=15, b=-31, and c=10




z+=+%2831+%2B-+sqrt%28+%28-31%29%5E2-4%2A15%2A10+%29%29%2F%282%2A15%29 Negate -31 to get 31




z+=+%2831+%2B-+sqrt%28+961-4%2A15%2A10+%29%29%2F%282%2A15%29 Square -31 to get 961 (note: remember when you square -31, you must square the negative as well. This is because %28-31%29%5E2=-31%2A-31=961.)




z+=+%2831+%2B-+sqrt%28+961%2B-600+%29%29%2F%282%2A15%29 Multiply -4%2A10%2A15 to get -600




z+=+%2831+%2B-+sqrt%28+361+%29%29%2F%282%2A15%29 Combine like terms in the radicand (everything under the square root)




z+=+%2831+%2B-+19%29%2F%282%2A15%29 Simplify the square root (note: If you need help with simplifying the square root, check out this solver)




z+=+%2831+%2B-+19%29%2F30 Multiply 2 and 15 to get 30


So now the expression breaks down into two parts


z+=+%2831+%2B+19%29%2F30 or z+=+%2831+-+19%29%2F30


Lets look at the first part:


x=%2831+%2B+19%29%2F30


z=50%2F30 Add the terms in the numerator

z=5%2F3 Divide


So one answer is

z=5%2F3




Now lets look at the second part:


x=%2831+-+19%29%2F30


z=12%2F30 Subtract the terms in the numerator

z=2%2F5 Divide


So another answer is

z=2%2F5


So our solutions are:

z=5%2F3 or z=2%2F5






Remember, we let z=x%5E2. So this means that


5%2F3=x%5E2 or 2%2F5=x%5E2


Take the square root of both sides for each case (remember the "plus/minus")


x=sqrt%285%2F3%29, x=-sqrt%285%2F3%29, x=sqrt%282%2F5%29, or x=-sqrt%282%2F5%29



Rationalize the denominator (if necessary)

x=sqrt%2815%29%2F3, x=-sqrt%2815%29%2F3, x=sqrt%2810%29%2F5, or x=-sqrt%2810%29%2F5


--------------------------------------
Answer:

So the solutions are

x=sqrt%2815%29%2F3, x=-sqrt%2815%29%2F3, x=sqrt%2810%29%2F5, or x=-sqrt%2810%29%2F5