Question

How do you factor `-x^2+7x+18`?

Answer 1

`f(x) = -x^2 + 7x + 18 = -(x - p)(x -q)`

Use the new AC Method to factor trinomials.
Compose factor pairs of (c = 18) and look for the pair whose sum is
(b = 7). Proceed: (-1, 18)(-2, 9). Since a < 0, Then, p = 2 and q = -9.
Factored form:

`f(x) = - (x + 2)( x - 9)`

Check: Develop f(x) = -(x^2 - 7x - 18) = -x^2 + 7x + 18. Correct.