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Answer 40667 by funmath(2925) on 2006-11-01 18:57:00 (Show Source):
You can put this solution on YOUR website!determine whether the following pairs of lines are perpendicular or not perpendicular
y=-x+4
y=x-3
:
These lines are in slope intercept form  , where m=slope and (0,b)=y-intercept.
Perpendicular lines have slopes that are negative reciprocals of each other, that means they are opposite signs and upside down, because of this quality, if we multiply their slopes we get -1  .
y=-x+4 -->>  m=-1
y=x-3 -->>  m=1
:
If you multiply their slopes -1*1=-1, therefore the lines are perpendicular.
Happy Calculating!!!
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Linear-systems/59323: what is 2x-3y=12
x=4y+1
substituion form 1 solutions
Answer 40664 by funmath(2925) on 2006-11-01 18:45:58 (Show Source):
You can put this solution on YOUR website!what is
L1) 2x-3y=12
L2) x=4y+1
substituion form
:
Substitute the right side of L2 into L1 for x and solve for y
2(4y+1)-3y=12
8y+2-3y=12
5y+2=12
5y+2-2=12-2
5y=10
5y/5=10/5
y=2
:
Substitute 2 in for y in L2 and solve for x
x=4(2)+1
x=8+1
x=9
The solution (x,y)=(9,2)
This is the point that both equations share. Garphically, its' the point of intersection of the two lines.
Happy Calculating!!!
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Linear-equations/59322: This question is from textbook
here's a table.
x y
4 14
8 15.5
12 17
16 18.5
i know the rate of change is 1.5, but how would i find the value of y when x=120?? how about finding the value of x when y=50?? 1 solutions
Answer 40661 by funmath(2925) on 2006-11-01 18:33:25 (Show Source):
You can put this solution on YOUR website!here's a table.
x y
4 14
8 15.5
12 17
16 18.5
How would i find the value of y when x=120?? how about finding the value of x when y=50??
Your rate of change is the slope between various points. I checked this out and this is indeed a linear relation.
The formula to find the slope between two points is:
You can choose any two points to find the slope, so let's choose the ones without decimals to make it a little easier.
(x1,y1)=(4,14) and (x2,y2)=(12,17)

We can now find the equation of the line using the point-slope formula:  , m=slope,(x1,y1)=any point on the line.
(x1,y1)=(4,14) and m=3/8

:
When x=120
3(120)-8y=-100
360-8y=-100
-360+360-8y=-360-100
-8y=-460
-8y/-8=-460/-8
y=115/2

:
When y=50
3x-8(50)=-100
3x-400=-100
3x-400+400=400-100
3x=300
3x/3=300/3

:
If I just blew your mind and you've never seen any of this before, another way you can do this is to plot the points on a graph and using graph paper and a ruler you can approximate the same thing.
:
Happy Calculating!!!
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Linear-equations/59321: This question is from textbook
how would i write an equation in point slope form, when it only gives me the coordinates: (-4,-6)?? 1 solutions
Answer 40659 by funmath(2925) on 2006-11-01 18:13:18 (Show Source):
You can put this solution on YOUR website!how would i write an equation in point slope form, when it only gives me the coordinates: (-4,-6)??
In order to make an equation of a line you're supposed to have a point AND a slope.
The point slope form is  , where m=slope and (x1,y1) is the given point.
Since you were only given: (x1,y1)=(-4,-6) all you can do is:
y-(-6)=m(x-(-4))
y+6=m(x+4)
Happy Calculating!!!
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Functions/59299: if f(x) =2x+5 find the following.
f(-4)
f(3)-5 1 solutions
Answer 40654 by funmath(2925) on 2006-11-01 17:53:48 (Show Source):
You can put this solution on YOUR website!if f(x) =2x+5 find the following.
:
f(-4) Substitute -4 in for x and simplify.
f(-4)=2(-4)+5
f(-4)=-8+5
f(-4)=-3
:
f(3)-5 Substitute 3 in for x subtract 5 and simplify.
f(3)-5=(2(3)+5)-5
f(3)-5=6+5-5
f(3)-5=6
:
Happy Calculating!!!
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Equations/59306: -8-t=-25
8=b-3+19
16=8+s
----
-7 (8+s over -7)
It would be very helpful if you could help me solve these problems. Thank you. 1 solutions
Answer 40650 by funmath(2925) on 2006-11-01 17:33:56 (Show Source):
You can put this solution on YOUR website!-8-t=-25
8-8-t=8-25
-t=-17
-(-t)=-(-17)

check by substituting 17 in for t and see if the sides are =.
-8-17=-25
-25=-25 We're right!!!
:
8=b-3+19
8=b+16
8-16=b+16-16
-8=b

Check:
8=(-8)-3+19
8=-11+19
8=8 We're right again!!!
:

Check:
 Three for three!!!
Happy Calculating!!!
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Mixture_Word_Problems/59288: You have 20 stampes that have a total value of $6.62. Some of the stamps are worth $0.24 each and others are worth $0.37 each. How many stamps of each type do you have? Please show how to solve this question. 1 solutions
Answer 40646 by funmath(2925) on 2006-11-01 17:08:36 (Show Source):
You can put this solution on YOUR website!You have 20 stampes that have a total value of $6.62. Some of the stamps are worth $0.24 each and others are worth $0.37 each. How many stamps of each type do you have?
It's easier to deal with money in terms of cents to avoid decimals.
Let the number of 24 cent stamps be:x
then because there is 20 stamps all together the number of 37 cent stamps is:20-x
The total value is: 662 cents
:
24x+37(20-x)=662
24x+740-37x=662
-13x+740=662
-13x+740-740=662-740
-13x=-78
-13x/-13=-78/-13
x=6
The number of 24cent stamps: x=6
The number of 37 cent stamps:20-x=20-6=14
:
Check, if you had 6 $.24 stamps and 14 $.37 stamps would the value be $6.62?
6(.24)+14(.37)=6.62 ?
1.44+5.18=6.62 ?
6.62=6.62 !!! We're right!!!
Happy Calculating!!!
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Number-Line/59287: This question is from textbook Holt Middle School Math
3t<=27
1 solutions
Answer 40637 by funmath(2925) on 2006-11-01 14:38:33 (Show Source):
You can put this solution on YOUR website!

Because t is less than or equal to 9, put either a closed circle or a ] over 9 and shade to the left over the numbers less than 9.
<<=================]---->
-1,0,1,2,3,4,5,6,7,8,9,10
Happy Calculating!!!
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Quadratic_Equations/59260: Would someone be able to help me through a couple of these so I can get a better grip on how to do them?
Determine the number of solutions to the quadratic equation using the discriminant to determine if the answers are real or complex. (no need to find the roots, just the numer & solution type)
i. 2x^2+5x+5=0
ii. 3z^2+z-1=0
Many thanks! 1 solutions
Answer 40631 by funmath(2925) on 2006-11-01 14:24:27 (Show Source):
You can put this solution on YOUR website!
Determine the number of solutions to the quadratic equation using the discriminant to determine if the answers are real or complex. (no need to find the roots, just the numer & solution type)
:
The discriminant of a quadratic equation written in standard form  is  Notice that this is just the inside of the square root in the quadratic equation.
If the discriminant is positive there are 2 real solutions.
If the discriminant is 0 there is one real solution.
If the discriminant is negative there are 2 complex solutions.
:
i. 2x^2+5x+5=0
a=2, b=5,c=5 The discriminant is
 negative. There are 2 complex solutions.
:
ii. 3z^2+z-1=0
a=3, b=1,c=-1 The discriminant is
 positive. There are two real solutions.
Happy Calculating!!!
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Proportions/59278: namethree fraction whose decimal equivalent is 0.40. 1 solutions
Answer 40627 by funmath(2925) on 2006-11-01 14:13:07 (Show Source):
You can put this solution on YOUR website!namethree fraction whose decimal equivalent is 0.40.
This is read 40 one-hundredths, so start there.
40/100
4/10 reduce the top and bottom by 10
2/5 reduce the top and bottom by 2
There's an infinite number of possibilities!!!
400/1000
6/15
12/30
What can you come up with?
Happy Calculating!!!
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Linear-systems/59266: This question is from textbook algebra 1
i dont understand how to do this problem:
y=3x-7
y=-x+1 1 solutions
Answer 40624 by funmath(2925) on 2006-11-01 14:07:33 (Show Source):
You can put this solution on YOUR website!y=3x-7
y=-x+1
We're looking for when their x=x and y=y, so set the problems equal to each other.
3x-7=-x+1
3x+x-7=x-x+1
4x-7=1
4x-7+7=1+7
4x=8
4x/4=8/4
x=2
Let x=2 and solve for y in one of the equations.
y=-(2)+1
y=-1
The solution is:(2,-1)
Graphically, it's their point of intersection:

Happy Calculating!!!
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Radicals/59274: I don't know if I am inputting this correctly, but I will try....
Use only radicals in answer:
^3(radical sign)-54x^15y^6 (all are under radical except ^3) 1 solutions
Answer 40620 by funmath(2925) on 2006-11-01 13:40:54 (Show Source):
You can put this solution on YOUR website!I haven't found an easy way of indicating cubed roots either. I've used: \3/ 
Find the perfect cubes within the radical sign.
\3/ 
\3/  Take the perfect cubes out and leave the rest inside the radical sign.
-3x^5*y^2\3/ 
-3x^5y^2 the cubed root of 2.
Happy Calculating!!!
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Functions/59178: Find the domain of the rational function:
f(x) = (2x^2 - 4) / (3x^2 + 6x - 45) 1 solutions
Answer 40611 by funmath(2925) on 2006-11-01 11:39:05 (Show Source):
You can put this solution on YOUR website!Find the domain of the rational function:

The domain of a simple rational function is all real numbers EXCEPT the numbers that make the denominator equal 0.

(x+5)(x-3)=0
x+5=0 and x-3=0
x=-5 and x=3 will make the denominator 0 and the fraction undefined.
Therefore the domain includes all real numbers except:-5, and 3.
set builder notation:{x|x not= -5,3}
interval notation:(-infinity,-5)U(-5,3)U(3,infinity)
Happy Calcualting!!!
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Exponential-and-logarithmic-functions/59245: Please find derivative and simplify:
y=ln(3x-5)^3/(5x+4)^4 1 solutions
Answer 40610 by funmath(2925) on 2006-11-01 11:11:17 (Show Source):
You can put this solution on YOUR website!Please find derivative and simplify:
d/dx[ln(x)]=1/x
d/dx[cf(x)]=cf'(x)
d/dx[c]=0
Chain Rule: d/dx[f(g(x))]=f'(g(x))*g'(x)
:
y=ln((3x-5)^3/(5x+4)^4) Use properties of logs to simplify first.
y=ln((3x-5)^3)-ln((5x+4)^4)
y=3ln(3x-5)-4ln(5x+4) Now take the derivative using the chain rule:

Happy Calculating!!!
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Quadratic_Equations/59229: Given the following quadratic function: f(x) = x squared - 2x - 8,
(1) Rewrite the function in vertex form. Identify the vertex. 1 solutions
Answer 40608 by funmath(2925) on 2006-11-01 11:01:24 (Show Source):
You can put this solution on YOUR website!Given the following quadratic function: f(x) = x ^2 - 2x - 8,
(1) Rewrite the function in vertex form. Identify the vertex.
Vertex form is:  , where (h,k)=vertex.
We need to create a perfect square trinomial by adding and subtracting the same number, so you are really only adding 0.
:
f(x)=x^2-2x-8
f(x)=(x^2-2x+__)-___-8 Fill the blanks with (1/2(-2))^2=(-1)^2=1

The vertex (h,k)=(1,-9)
Happy Calculating!!!
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Quadratic_Equations/59230: This question is from textbook elementary and intermediate algebra
Use the discriminant to determine whether or not the quadratic 2x^2 + 3x + 2
is prime. If it is not prime, factor it. 1 solutions
Answer 40607 by funmath(2925) on 2006-11-01 10:42:43 (Show Source):
You can put this solution on YOUR website!Use the discriminant to determine whether or not the quadratic 2x^2 + 3x + 2
is prime. If it is not prime, factor it.
The discriminant of a quadratic equation written in standard form:  is  , if this is negative there is no real number solution, if it's not a perfect square, it's not factorable.
:
a=2, b=3, and c=2
:
 It's not factorable and has no real solution.
Happy Calculating!!!
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Functions/59236: Please Find the Derivatives of the following and simplify:
y=5e^3x
y=1/e^x
y=e^3
y=e^x2e^2x
Thanks!
1 solutions
Answer 40602 by funmath(2925) on 2006-11-01 10:00:54 (Show Source):
You can put this solution on YOUR website!Find the Derivatives of the following and simplify:
d/dx[cf(x)]=cf'(x)
d/dx[e^x]=e^x
d/dx[c]=0
The chain rule: d/dx[f(g(x)]=f'(g(x))g'(x)
:
 Use the chain rule:

:
 ---->>  Use the chain rule again:

:
There is no x, this is a constant even though it doesn't look like one.  . The derivative of a constant is 0.

:
I'm not sure if I'm interpretting you right on this one, let me know if there's a misunderstanding!!!
 -------->>  --->>  Use chain rule:

:
Happy Calculating!!!
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Radicals/59237: simplify, use only radicals in answer:
(radical sign) (6x^8y^4)/8 (everything is under radical)
I just don't get it!!!! 1 solutions
Answer 40598 by funmath(2925) on 2006-11-01 09:30:42 (Show Source):
You can put this solution on YOUR website!This is an unusual request, I hope I'm understanding what you want with the radicals.
simplify, use only radicals in answer:
 Find your perfect squares
 Take them out

Happy Calculating!!!
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Money_Word_Problems/59218: Ms. Jordan has been given a loan of $2500 for 1 year. If the interest charged is $275, what is the interest rate on the loan? 1 solutions
Answer 40592 by funmath(2925) on 2006-11-01 06:55:30 (Show Source):
You can put this solution on YOUR website!Ms. Jordan has been given a loan of $2500 for 1 year. If the interest charged is $275, what is the interest rate on the loan?
The formula for simple interest is:  , where I=interest, P=principle, r=rate, t=time.
For this problem:
P=2500
t=1
I=275

If they ask for the answer in percentage multiply this by 100%.
 %
r=11%
Happy Calculating!!!
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Money_Word_Problems/59220: The electricity costs of a business decreased from $12,000 one year to $10,920 the next. What is the rate of decrease? 1 solutions
Answer 40590 by funmath(2925) on 2006-11-01 06:46:05 (Show Source):
You can put this solution on YOUR website!The electricity costs of a business decreased from $12,000 one year to $10,920 the next. What is the rate of decrease?

:
If you need this in percentage, multiply this by 100%
 %
-9%
The negative indicates a 9% decrease. If you say decrease, you don't need to say it was negative.
:
Happy Calculating!!!
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