The first, and in my opinion most important rule of factoring is to factor out the greatest common factor, in this case, 5
5(4x^2-9y^2)
Now factor the difference of the two perfect squares.
5(2x+3y)(2x-3y)
2006-10-13 12:22:28
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answer #1
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answered by mom 7
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First, find the greatest common factor of both terms
20x^2 and 45y^2 have a GCF of 5 so we are going to pull it out to the front and factor it from each term by dividing
20x^2 - 45y^2
5*(20x^2/5 - 45y^2/5)
5*(4x^2 - 9y2)
Now, the factor in the parenthesis is the difference of two perfect squares so it factors into the sum and difference of the square root of each like this
5*(2x+3y)(2x-3y)
That's it
You can check by usingfoil and the distributive property to multiply you answer out and see if you get the original problem back.
2006-10-13 19:26:53
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answer #2
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answered by momogriff 2
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Remember, always take out the common factor first. That's 5, and then the expression inside the parentheses is a difference of squares, which you can factorise as
a^2 - b^2 = (a + b)(a - b).
Hope you can do this yourself, but some other answerer probably will complete it for you (or already has); if not, contact me at
h_chalker@yahoo.com.au
2006-10-13 19:25:01
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answer #3
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answered by Hy 7
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1st factor out 5 to get 5(4x^2-9y^2)
This is of the form a^2-b^2 which can be factored
a^2-b^2=(a+b)(a-b).
here a=2x &
b=3y so
20x^2 - 45y^2=5(4x^2-9y^2)=5(2x+3y)(2x-3y)
2006-10-17 16:26:10
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answer #4
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answered by yupchagee 7
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20x^2 - 45y^2 = 5(4x^2 - 9y^2) = 5(2x - 3)(2x + 3)
2006-10-13 22:39:30
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answer #5
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answered by Sherman81 6
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= 5 * (4*x^2 - 9*y^2)
= 5 * (2x-3y) (2x+3y)
2006-10-13 19:23:05
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answer #6
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answered by mike 1
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(2x-3y)*(10x+15y)
2006-10-13 19:26:37
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answer #7
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answered by bruinfan 7
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