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i need to factor

x^3-5x^2-xy^2+5y^2

i grouped them like this

{x^3-xy^2}{-5x^2+5y^2}

then

x(x^2-y^2)-5(x^2+y^2)

followed by

x(x+y)(x-y)-5(x^2+y^2)

I'm not too sure if i did it right and would apreciate the help as this is for my learning guide

 Sep 16, 2016

Best Answer 

 #1
avatar+23252 
+5

x3 - 5x2 - xy2 + 5y2

When you grouped them you got:

x3 - xy2 - 5x2 + 5y2

Now, when you factor out the minus sign from the last two terms, you should get:

x3 - xy2 - (5x2 - 5y2)      <---  Notice the minus sign in from of the 5y2 term (because the minus was factored out)

Continuing:

x(x2 - y2) - 5(x2 - y2)

(x2 - y2)(x - 5)

(x + y)(x - y)(x - 5)

 Sep 16, 2016
 #1
avatar+23252 
+5
Best Answer

x3 - 5x2 - xy2 + 5y2

When you grouped them you got:

x3 - xy2 - 5x2 + 5y2

Now, when you factor out the minus sign from the last two terms, you should get:

x3 - xy2 - (5x2 - 5y2)      <---  Notice the minus sign in from of the 5y2 term (because the minus was factored out)

Continuing:

x(x2 - y2) - 5(x2 - y2)

(x2 - y2)(x - 5)

(x + y)(x - y)(x - 5)

geno3141 Sep 16, 2016
 #2
avatar
+5

Factor the following:
x^3-5 x^2-x y^2+5 y^2

Factor terms by grouping. x^3-5 x^2-x y^2+5 y^2 = (5 y^2-x y^2)+(x^3-5 x^2) = x^2 (x-5)-y^2 (x-5):
x^2 (x-5)-y^2 (x-5)

Factor x-5 from x^2 (x-5)-y^2 (x-5):
(x-5) (x^2-y^2)

Factor the difference of two squares. x^2-y^2 = (x-y) (x+y):
Answer: |(x-y) (x+y) (x - 5)

 Sep 16, 2016

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