need help factorizing please
4(x-2)^2-9(x-1)^2
can be show working out and formula to like. eg. different of two squared: a^2-b^2 = (a-b)(a+b)
October 9, 2011
need help factorizing please
4(x-2)^2-9(x-1)^2
can be show working out and formula to like. eg. different of two squared: a^2-b^2 = (a-b)(a+b)
4 Comments • Newest first
Since people already derived -5x^2 + 2x + 7,
factorised, it's (-5x+7)(x+1).
4(x-2)^2-9(x-1)^2
4(x^2-4x+4)-9(x^2-2x+1)
4x^2-16x+16-9x^2+18x-9
-5x^2+2x+7
Doesn't look like a factorise question though...
LOLS. I accidentally figured it out. You square root the front number and multiple into the bracket numbers. After expand the squared brackets, and after use A^2-B^2 method. My bad guys.
Edit: LOLS. It funny that all your answers are similar in a way. It ask to factorise not expand.
4(x-2)^2-9(x-1)^2
= 4(x-2)(x-2)-9(x-1)(x-1)
= 4(x^2-4x+4)-9(x^2-2x+1)
= (4x^2-16x+16)-(9x^2-18x+1)
= 4x^2-16x+16-9x^2+18x-1
= -5x^2+2x+15
I think that's right....