Algebra-1

Since one of the factors of -x² + mx - 20 is -(x + 4), let the other factor be (x + a).

Then -x² + mx - 20 = -(x + 4)(x + a) = -(x² + (4 + a)x +4a).

So -x² +mx - 20 = -x² - (4 +...