Question

Please answer !! what is the factorization of the trinomial below ?

-x² + x + 42
A. -1(x - 7)(x + 6)
B. (-x + 6)(x + 7)
C. (x + 6)(x - 7)
D. -1(x + 7)(x + 6)

Answer 1

Since we always want to have an a which equals 1 so then we don't have to do AC method, a longer process, we're going to want to take out the -1.

-1(x^2 - x - 42)

Then, we want to know what two number multiply to equal c (-42 here) and add up to equal b (-1 here). Those two numbers would be -7 and 6 since -7(6) = -42 and -7 + 6= -1.

So then from here we can just plop these numbers into (x+ __).

1(x-7)(x+6)

This is your final answer, A.