Answer:
(x +6)(x -7)
Step-by-step 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)
