Medium
Find the roots of the quadratic equation x² + (-8)x + (15) = 0.
Explanation
Explanation
We need two numbers whose sum is 8 and product is 15 (since for x² + bx + c, sum of roots = -b, product = c). Those numbers are 5 and 3, so the equation factors as (x - (5))(x - (3)) = 0, giving x = 5 or x = 3.
PRO TIP
Re-check your working by substituting the answer back into the original question.