Question

x² + 4x - 21

Explanation:

Step1: Find factors of -21 that sum to 4

We need two numbers: $7$ and $-3$, since $7 \times (-3) = -21$ and $7 + (-3) = 4$.

Step2: Rewrite as factored binomials

Substitute the factors into the form $(x + a)(x + b)$

Answer:

$(x + 7)(x - 3)$