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Earlsdon answered: 6281 problems
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expressions/507585: X^2 - 9=0 factor
1 solutions

Answer 340588 by Earlsdon(6287) About Me  on 2011-10-01 15:28:34 (Show Source):
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Factor:
x%5E2-9 This is a difference of squares, and A%5E2-B%5E2+=+%28A-B%29%28A%2BB%29 and...
x%5E2-9+=+%28x-3%29%28x%2B3%29


Percentage-and-ratio-word-problems/507556: If a dose of 100 milligrams is contained in 4 cubic centimeters how many cubic centimeters are in 40 milligrams?
1 solutions

Answer 340586 by Earlsdon(6287) About Me  on 2011-10-01 15:26:20 (Show Source):
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100mg = 4cc. Multiply both sides by 0.4 because 0.4%28100%29+=+40mg.
0.4%28100%29+=+0.4%284%29
40+=+1.6 so...
1.6cc are contained in 40mg. (cc. = cubic centimeters)


Angles/507571: find measure of an angle that is half as large as its complement

1 solutions

Answer 340583 by Earlsdon(6287) About Me  on 2011-10-01 15:19:48 (Show Source):
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Let the angle be A, then its complement is (90-A), so...
A+=+%281%2F2%29%2890-A%29 Simplify. Multiply by 2.
2A+=+90-A Add A to both sides.
3A+=+90 Divide by 3.
A+=+30degrees.


Numbers_Word_Problems/507576: The sum of two consecutive numbers is 117. What are the two numbers?
1 solutions

Answer 340579 by Earlsdon(6287) About Me  on 2011-10-01 15:07:32 (Show Source):
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Two consecutive numbers can be expressed as:
x and x+1, so...
x+(x+1) = 117 Simplify.
2x+1 = 117 Subtract 1.
2x = 116 Divide by 2.
x = 58.
So the two numbers are:
58 and 59.


real-numbers/507533: Can you please help me solve 8w-8-6w=4w-7
here's what I did:
8w-8-6w=4w-7
8w-6w=2w
2w-8=4w-7
-4w -4w
-2w-8=-7
+8 +8
-2w=1
-2w/-2
1/-2
and I got -.5. But when I plugged it in I got -9 not -7.
1 solutions

Answer 340521 by Earlsdon(6287) About Me  on 2011-10-01 12:16:44 (Show Source):
You can put this solution on YOUR website!
It looks like you did everything right and you got the correct answer.
Let's check:
8w-8-6w+=+4w-7 Now substitute your answer of w+=+-1%2F2
8%28-1%2F2%29-8-6%28-1%2F2%29+=+4%28-1%2F2%29-7 Evaluate.
-4-8%2B3+=+-2-7
-12%2B3+=+-9
-9+=+-9
You did good!


Percentage-and-ratio-word-problems/507519: A young man is the beneficiary of a trust fund established for him 16 yr ago at his birth. If the original amount placed in trust was $40,000, how much will he receive if the money has earned interest at the rate of 9%/year compounded annually? Compounded quarterly? Compounded monthly? (Round your answers to the nearest cent.)


compounded annually ?
compounded quarterly ?
compounded monthly ?

1 solutions

Answer 340520 by Earlsdon(6287) About Me  on 2011-10-01 12:10:16 (Show Source):
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You can use the compound interest formula to get your answers:
A+=+P%281%2Bi%2Fq%29%5Enq
A = The present amount (your answer).
P = the principal amount invested (P = $40,000).
i = the rate of interest, expressed as a decimal (i = 0.09).
q = The number of compounding periods per year (q = 1 for annually, 4 for quarterly, and 12 for monthly).
n = number of years (n = 16).
Compounded annually:
A+=+P%281%2Bi%2Fq%29%5Enq Substitute P = 40000, i = 0.09, q = 1 (once per year), and n = 16:
A+=+40000%281%2B0.09%29%5E16 Use your calculator.
A+=+158812.24
A = $158,812.24
Compounded quarterly:
A+=+P%281%2Bi%2Fq%29%5Enq Substitute P = 40000, i = 0.09, q = 4 (4 times per year), and n = 16.
A+=+40000%281%2B0.09%2F4%29%5E%284%2A16%29 Use your calculator.
A+=+166154.56
A = $166,154.56
You should now be able to do the last one yourself using the same formula and the same numbers except that q = 12 (for 12 times per year).


Functions/507517: I seem like I understand it and then when i get to the test I feel like i like blanked out especially with functions

1 solutions

Answer 340518 by Earlsdon(6287) About Me  on 2011-10-01 11:52:06 (Show Source):
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Isn't that the truth! This is not an uncommon phenomenon.
Do you have a specific problem that you'd like help with?


Volume/507523: 60 milliliters of water is equal to how many cubic centimeters of water?
1 solutions

Answer 340517 by Earlsdon(6287) About Me  on 2011-10-01 11:43:10 (Show Source):
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You can work this out yourself when you realise that:
1 cubic entimeter = 0.999972 milliliters.
For all practical purposes:
1 cc. = 1 ml.


Exponential-and-logarithmic-functions/507520: solve log(3x+4)=2log(x)
1 solutions

Answer 340515 by Earlsdon(6287) About Me  on 2011-10-01 11:38:48 (Show Source):
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Solve:
Log%283x%2B4%29+=+2Log%28x%29 Apply the "power rule" to the right side.
Log%283x%2B4%29+=+Log%28x%5E2%29 Now if Log%28M%29+=+Log%28N%29 then M+=+N so...
3x%2B4+=+x%5E2 Rearrange as:
x%5E2-3x-4+=+0 Solve by factoring:
%28x%2B1%29%28x-4%29+=+0 Apply the "zero product" rule:
x%2B1+=+0 or x-4+=+0 so that...
x+=+-1 or x+=+4
Now you must check the results for "extraneous" or "invalid" values:
Try x+=+-1
Log%283x%2B4%29+=+2Log%28x%29 Substitute x+=+-1
Log%283%28-1%29%2B4%29+=+2Log%28-1%29
Log%281%29+=+2Log%28-1%29
0+=+2%281.364376%29i This is not valid!
Try x+=+4
Log%283x%2B4%29+=+2Log%28x%29 Substitute x+=+4
Log%2816%29+=+2Log%284%29
1.20411998+=+2%280.60205999%29
1.20411998+=+1.20411998 This is valid.
Solution is x+=+4


Age_Word_Problems/507474: ten years ago the age of a father was four times of his son . Ten years hence the age of the father will be twice that of his son . The present ages of the father and the son are.
1 solutions

Answer 340503 by Earlsdon(6287) About Me  on 2011-10-01 10:33:51 (Show Source):
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Let D = Dad's present age and S = Son's present age.
1) D-10 = 4(S-10) "Ten years ago the age of a father (D-10) was four times the age of his son (4(S-10))."
2) D+10 = 2(S+10) "Ten years hence, the age of the father (D+10) will be twice that of his son ((2(S+10))."
So now you have two equations with two unknowns (D & S). Simplify the two equations:
1a) D-10 = 4S-40
2a) D+10 = 2S+20 Subtract equation 2a) from equation 1a) to get:
3) -20 = 2S-60 Now add 60 to both sides.
3a) 40 = 2S Divide both sides by 2.
3b) 20 = S or S = 20 Now substitute this value of S into 1a) or 2a) and solve for D.
2a) D+10 = 2S+20 Substitute S = 20
2b) D+10 = 2(20)+20 Simplify.
3c) D+10 = 60 Subtract 10 from both sides.
3d) D = 50
The father is 50 years old and the son is 20 years old.


Miscellaneous_Word_Problems/507063: 1. Which has the greater area, a square with sides x + 1 units long or a rectangle with lengths x + 2 units and width x units? How much greater?

1 solutions

Answer 340326 by Earlsdon(6287) About Me  on 2011-09-29 22:47:18 (Show Source):
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The area of the square with sides of (x+1) is:
A%5Bs%5D+=+%28x%2B1%29%28x%2B1%29
A%5Bs%5D+=+x%5E2%2B2x%2B1
The area of the rectangle with sides (x+2) and (x) is:
A%5Br%5D+=+%28x%2B2%29%28x%29
A%5Br%5D+=+x%5E2%2B2x
Subtract the area of the rectangle from the area of the square:
x%5E2%2B2x%2B1
-(x%5E2%2B2x)
-----------
1 The area of the square is larger by 1 square unit.


Systems-of-equations/507045: a chemist has one solution that is 25% acid and a second that is 50% acid. how many liters of each should be mixed to get 10 L of a solution that is 40% acid?
1 solutions

Answer 340323 by Earlsdon(6287) About Me  on 2011-09-29 22:38:10 (Show Source):
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Let x = the required number of liters of the 25% acid solution, then (10-x) is the required number of liters of the 50% acid solution. These are mixed to obtain 10 liters (x+(10-x)) of 40% acid solution. Let's write the equation to solve for x after changing the percentages to their decimal equivalents.
0.25x+0.5(10-x) = 0.4(10) Simplify.
0.25x+5-0.5x = 4 Combine the x-terms.
-0.25x+5 = 4 Subtract 5 from both sides.
-0.25x = -1 Finally, divide both sides by -0.25
x = 4 and 10-x = 6, so...
The chemist will need to mix 4 liters of the 25% acid solution with 6 liters of the 50% acid solution to obtain 10 liters of 40% acid solution.


Average/507026: On the three tests of 100 points each, Takia has an 87 average. What is the lowest score she could earn on the next test to have an 90 average?
1 solutions

Answer 340317 by Earlsdon(6287) About Me  on 2011-09-29 22:22:12 (Show Source):
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Let the scores of the first three tests be a, b, and c. Then:
%28a%2Bb%2Bc%29%2F3+=+87 To find the sum of the first three test scores, multiply both sides by 3.
a%2Bb%2Bc+=+261 Now let the fourth test score be x, so...
%28a%2Bb%2Bc%2Bx%29%2F4+%3E=+90 Substitute a%2Bb%2Bc+=+261
%28261%2Bx%29%2F4+%3E=+90 Multiply both sides by 4.
261%2Bx+%3E=+360 Subtract 261.
x+%3E=+99
Takia must score at least 99 points on the fourth test to achieve an overall average of 90.


Complex_Numbers/507035: Hello! I was hoping someone could help me with sq. roots! I apologize I am new at this and any help is appreciated!!!
Thank you!!! :)
Simplify the following expression.
sq.rt -98 sq.rt. -50
1 solutions

Answer 340312 by Earlsdon(6287) About Me  on 2011-09-29 22:08:16 (Show Source):
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Simpl;ify:
%28sqrt%28-98%29%29%2A%28sqrt%28-50%29%29+=+sqrt%28%28-98%29%2A%28-50%29%29 Evaluate this:
sqrt%284900%29+=+70 or -70


Polynomials-and-rational-expressions/505365: Factor by grouping, if possible, and check.
52.
5x^3 + 4x^2 − 10x − 8
Will someone please help me with this problem, I need help quickly if possible.
1 solutions

Answer 339876 by Earlsdon(6287) About Me  on 2011-09-27 16:14:50 (Show Source):
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Factor by grouping:
5x%5E3%2B4x%5E2-10x-8 Group as shown:
highlight%285x%5E3%2B4x%5E2%29-highlight%28%2810x%2B8%29%29 Factor as shown:
x%5E2%2Ahighlight_green%28%285x%2B4%29%29-2%2Ahighlight_green%28%285x%2B4%29%29 Now factor the highlight_green%285x%2B4%29
highlight%28%28x%5E2-2%29%285x%2B4%29%29 You can check the answer by multiplying the two factors.


Polynomials-and-rational-expressions/505366: #24.Factor completely. If a polynomial is prime, state this.
9 + 8t^2 − 18t

74.Factor completely. Remember to look first for a common factor. If a polynomial is prime, state this.
24x^2 − 54

Hi math friends can I please get help with these problems.These are my last questions please help me I greatly appreciate it!!
I don't understand.
1 solutions

Answer 339872 by Earlsdon(6287) About Me  on 2011-09-27 16:04:12 (Show Source):
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Factor:
24) 9%2B8t%5E2-18t Rearrange as:
8t%5E2-18t%2B9 = highlight%28%282t-3%29%284t-3%29%29
74) 24x%5E2-54 Factor out a 6.
6%284x%5E2-9%29 Factor the difference of squares.
highlight%286%282x%2B3%29%282x-3%29%29


Miscellaneous_Word_Problems/505375: 5 years from now rosa will be more than twice as old as she is now. What can you say about her age today? Inequality word problems
1 solutions

Answer 339870 by Earlsdon(6287) About Me  on 2011-09-27 15:53:22 (Show Source):
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Let R = Rosa's present age, then...
R%2B5+%3E+2R Solve for R. Subtract R from both sides.
5+%3E+R so...
Rosa's present age is less than 5 years.


logarithm/505121: Please help us solve this log. prob my Maths teacher is also confused:
log x = 1/3 log 8 + log 9 - 1/3 log 27
Thank you in advance.
1 solutions

Answer 339781 by Earlsdon(6287) About Me  on 2011-09-26 23:06:19 (Show Source):
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Logx+=+%281%2F3%29Log8%2BLog9-%281%2F3%29Log27 First, apply the "power rule" for logarithms:
n%2ALogM+=+LogM%5En
Logx+=+Log8%5E%281%2F3%29%2BLog9-Log27%5E%281%2F3%29 Substitute 8%5E%281%2F3%29+=+2 and 27%5E%281%2F3%29+=+3
Logx+=+Log2%2BLog9-Log3 Now apply the "product rule" for logarithms:
LogM%2BLogN+=+Log%28M%2AN%29
Logx+=+Log%282%2A9%29-Log3 Now apply the "quotient rule" for logarithms:
LogM-LogN+=+Log%28M%2FN%29
Logx+=+Log%2818%2F3%29
Logx+=+Log6 and if LogM+=+LogN then M+=+N so...
highlight%28x+=+6%29


Quadratic-relations-and-conic-sections/505123: hello my name is heissem I'm in the 8th grade and have a algerbra question about distributive property. I have a worksheet of 25 problems but my teachers student aid didn't explain it (my teacher left class) and it is due tomorrow I have finished all but nine problems. they are asking me to use distributive property to show that the following statements are true. 3x +4x = 7x

1 solutions

Answer 339780 by Earlsdon(6287) About Me  on 2011-09-26 22:54:35 (Show Source):
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3x+4x Factor out the x.
(3+4)x = 7x


Mixture_Word_Problems/505087: an auto mechanic needs 24 gallons of ani-freeze with a 30 percent glycol concentration. he has on hand only anit-freeze with a 40 percent glycol concentration and one with a 10 percent glycol concentration. How much of the 40 percent should he mix with the 10 percent to get the 24 gallons of 30 percent solution he needs?
1 solutions

Answer 339777 by Earlsdon(6287) About Me  on 2011-09-26 22:47:16 (Show Source):
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Let x = the required number of gallons of the 40% glycol solution. This is to be added to (24-x) gallons of the 10% glycol solution to obtain 24 gallons of 30% glycol solution. The equation to solve for x is:
0.4x+0.1(24-x) = 0.3(24)
0.4x+2.4-0.1x = 7.2 Simplify.
0.3x+2.4 = 7.2
0.3x = 4.8
x = 16 gallons and (24-x) = 8 gallons.
The mechanic will need to mix 16 gallons of the 40% glycol solution with 8 gallons of the 10% glycol solution to obtain 24 gallons of 30% glycol solution.


Polynomials-and-rational-expressions/505085: (3 x^2 +18x)/
(x^3 + 216)
1 solutions

Answer 339774 by Earlsdon(6287) About Me  on 2011-09-26 22:30:04 (Show Source):
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Simplify(?):
%283x%5E2%2B18x%29%2F%28x%5E3%2B216%29 Factor the numerator and the denominator:
3x%2Across%28%28x%2B6%29%29%2Fcross%28%28x%2B6%29%29%28x%5E2-6x%2B36%29=highlight%283x%2F%28x%5E2-6x%2B36%29%29


Miscellaneous_Word_Problems/504161: solving max/min problems: the sum of two positive number is 56.Find the two numbers,if their product ia amaximum.
1 solutions

Answer 339528 by Earlsdon(6287) About Me  on 2011-09-25 18:53:44 (Show Source):
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If the two numbers are a and b, then a+b = 56 which can be written as a = 56-b.
Now a*b must be a maximum (call it y)so we can write a*b as:
y+=+%2856-b%29%2Ab Simplify.
y+=+56b-b%5E2 This is a quadratic equation and the graph will be a parabola opening downward.
So all you need to do to find the maximum is find the value of b at the point of the parabola's vertex which is given by:
b+=+-56%2F2%28-1%29
b+=+28
So the two numbers are: a = 28 and b = 28.


decimal-numbers/503581: The binary number 1001 is equivalent to what base eight number
1 solutions

Answer 339314 by Earlsdon(6287) About Me  on 2011-09-24 17:41:17 (Show Source):
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Reading from right-to-left (like arabic), the binary number 1001 can be read as:
1X2%5E0+0X2%5E1+0X2%5E1+1X2%5E3=9 in decimal.
The octal (base 8)equivalent is highlight%2811%29 and this is deciphered as follows:
Group the digits of the binary number in groups of three starting from the right sides thus:
highlight%281%29highlight%28001%29 which is 11
In octal (base 8) the binary-to octal conversion looks like:
000+=+0
001+=+1
010+=+2
011+=+3
100+=+4
101+=+5
110+=+6
111+=+7
1000+=+10
1001+=+11
1010+=+12
1011+=+13


Polygons/502196: how can i solve this question because all i get is decimals when i try:
a regular polygon has an exterior angle with a measure of 20 degrees. find the numbers of sides
1 solutions

Answer 338803 by Earlsdon(6287) About Me  on 2011-09-21 22:34:11 (Show Source):
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In a regular polygon of n sides, the measure of an internal angle is given by:
%28n-2%29180%2Fn
An internal angle and the corresponding external angle are complementary so that if the external angle is 20 degrees then the corresponding internal angle is 180-20 = 160 degrees.
%28n-2%29180%2Fn+=+160 Solve for n.
%28n-2%29180+=+160n
180n-360+=+160n Subtract 160n from both sides.
20n-360+=+0 Add 360 to both sides.
20n+=+360 Divide by 20.
n+=+18
The regular polygon has 18 sides.


Miscellaneous_Word_Problems/502217: in a coffee shop the raito of the number of customers who ordered regular coffee to the number who ordered decaffeinated coffee was 4 to 1. if the number of perople who ordered regular coffee was 126 more than the number who ordered decaf, how many people ordered each tyoe of coffee?
1 solutions

Answer 338800 by Earlsdon(6287) About Me  on 2011-09-21 22:19:11 (Show Source):
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Let x = the number of customers who ordered decaffeinated coffee, then x+126 cutomers ordered regular coffee, so we can right a proportion:
4%2F1+=+%28x%2B126%29%2Fx Solve for x. Cross-multiply.
4x+=+x%2B126 Subtract x from both sides.
3x+=+126 Divide both sides by 3.
x+=+42
42 customers ordered decaffeinated coffee and 168 (42+126) customers ordered regular coffee.
Check:
168%2F42+=+4%2F1


Triangles/502224: " How do you solve a triangles height and base when you are only given the area, such as this-" A triangle has an area of 338, if the height of the triangle is 4 times its base, what is the height and base?"
1 solutions

Answer 338798 by Earlsdon(6287) About Me  on 2011-09-21 22:08:02 (Show Source):
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Start with:
A+=+%281%2F2%29b%2Ah for the area of a triangle. A is given as 338.
h+=+4b now you can write the equation.
%281%2F2%29b%2Ah+=+338 Substitute h+=+4b
%281%2F2%29%28b%284b%29%29+=+338 Simplify the left side.
2b%5E2+=+338 Divide both sides by 2.
b%5E2+=+169 Take the square root of both sides.
b+=+13 and...
h+=+4b
h+=+4%2813%29
h+=+52
The base is 13 and the height is 52.


Distributive-associative-commutative-properties/502232: how do i solve 2x-5(x-3)=2(x-10). Show work. answer is 7 but i cannot get it

1 solutions

Answer 338789 by Earlsdon(6287) About Me  on 2011-09-21 21:57:58 (Show Source):
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2x-5%28x-3%29+=+2%28x-10%29 Simplify by using the "distributive property".
2x-5x%2B15+=+2x-20 Subtract 2x from both sides.
-5x%2B15+=+-20 Subtract 15 from both sides.
-5x+=+-35 Finally, divide both sides by -5.
highlight%28x+=+7%29


Age_Word_Problems/502219: please help me solve this word problem: Jack is six years more than five times as old as Jill. if the sum of their ages is 78. how old is each?
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Answer 338786 by Earlsdon(6287) About Me  on 2011-09-21 21:50:03 (Show Source):
You can put this solution on YOUR website!
Let Ja be Jack's present age and Ji be Jill's present age.
1) Ja + Ji = 78 "...the sum of their ages is 78."
2) Ja = 5Ji+6 "Jack is six years more than five times as old as Jill." Rewrite equation 1) as:
1a) Ja = 78-Ji and substitute for Ja in equation 2) to get:
2a) 78-Ji =5Ji+6 Solve for Ji. Add Ji to both sides
2b) 78 = 6Ji+6 Now subtract 6 from both sides.
2c) 72 = 6Ji Finally, divide both sides by 6.
2d) 12 = Ji Jill is 12 years old.
1b) Ja = 78=Ji
1c) Ja = 78-12
1d) Ja = 66 Jack is 66 years old.


absolute-value/502207: |x^2+6x|=3x+18
I'm actually a college student trying to help my foreign exchange student with her high school algebra homework. Alas, I have forgotten how to work problems with absolute values. Any help would be wonderful!
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Answer 338783 by Earlsdon(6287) About Me  on 2011-09-21 21:37:46 (Show Source):
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abs%28x%5E2%2B6x%29+=+3x%2B18 Remove the absolute-value bars from the left side and you get two equations thus:
1) x%5E2%2B6x+=+3x%2B18 or 2) x%5E2%2B6x+=+-%283x%2B18%29 Now solve each of these equations for x.
1) x%5E2%2B6x+=+3x%2B18 Rewrite as a quadratic equation in standard form:
x%5E2%2B3x-18+=+0 Factor this quadratic equation.
%28x-3%29%28x%2B6%29+=+6 Apply the "zero product" rule:
x-3+=+0 or x%2B6+=+0 so that...
highlight%28x+=+3%29 or highlight%28x+=+-6%29
2) x%5E2%2B6x+=+-%283x%2B18%29 Simplify the right side.
x%5E2%2B6x+=+-3x-18 Rewrite as a quadratic equation in standard form:
x%5E2%2B9x%2B18+=+0 Factor this quadratic equation.
%28x%2B3%29%28x%2B6%29+=+0 Apply the "zero product" rule:
x%2B3+=+0 or x%2B6+=+0 so that...
highlight%28x+=+-3%29 or highlight%28x+=+-6%29


Age_Word_Problems/500741: my question is:
max and kay are cousins. the sum of their ages are 25. kay is two years less than twice the age of max. how old is max?
if you can please help me solve this i would be really grateful. if you have time can you please show the work cause i never understand these problems. thank you for your time
1 solutions

Answer 338261 by Earlsdon(6287) About Me  on 2011-09-19 21:30:02 (Show Source):
You can put this solution on YOUR website!
Let K = Kay's age and M = Max's age.
highlight%28K%29%2BM+=+25 "...the sum of their ages (is) 25."
highlight%28K+=+2M-2%29 "Kay is two years less than twice the age of Max." Substutute this into the first equation.
highlight%28%282M-2%29%29%2BM+=+25 Simplify and solve for M.
3M-2+=+25 Add 2 to both sides.
3M+=+27 Divide both sides by 3.
M+=+9
Max is 9 years old.


Trigonometry-basics/499683: need help on this problem y to the 5th power plus 7y to the 3rd power plus 12y.
1 solutions

Answer 337824 by Earlsdon(6287) About Me  on 2011-09-18 12:46:46 (Show Source):
You can put this solution on YOUR website!
Do you want to factor this expression?
y%5E5%2B7y%5E3%2B12y First factor a y from each term.
y%28y%5E4%2B7y%5E2%2B12%29 Now factor the trinomial.
highlight%28y%28y%5E2%2B4%29%28y%5E2%2B3%29%29...and that's the best you can do!