Factorise the following by using identities:- (Also mention the identity used)
-x^2-10x-25
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Answered by
9
-x^2-10x-25
-x^2-5x-5x-25
-x(x+5)-5(x+5)
(x+5)(-x-5)
-x^2-5x-5x-25
-x(x+5)-5(x+5)
(x+5)(-x-5)
Anonymous:
Which identity
I guess u used the identity (a+b)(a-b)= a^2-b^2
no i just used factorisation by substitution
i dont think it can be solved by identity
is there - before x^2
Oh okay...thanks
Answered by
6
By factorization method
- x^2-10x -25 =0
- x^2 -(5+5)x - 25 =0
-x^2 -5x -5x -25 =0
-x (x+5) -5 (x+5) =0
(x+5)(-x-5) =0
When (x+5) =0
x = -5 ans.
When (-x-5) =0
x= 5 ans.
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