Question

How do I factor this quadratic expression as the product of two binomials
x^2-x-42

Answer 1

(x +6)(x -7)

Explanation:

Look for factors of -42 (the constant) that have a sum of -1 (the x coefficient).

-42 = 1×-42 = 2×-21 = 3×-14 = 6×-7

Sums of these factor pairs are -41, -19, -11, and -1. The last two factors are the ones that are the constants in your binomial terms:

x^2 -x -42 = (x +6)(x -7)