Use Vieta's formula for x² + px + q = 0. For this form, the sum of the roots is -p and the product of the roots is q. The given roots are 5 and -1, so their sum is 5 + -1 = 4. Since sum = -p, we have -p = 4, which gives p = -4. The product 5×-1 = -5 also matches the constant term, so the roots are consistent. Therefore the correct answer is -4.