Hard
Find the roots of the quadratic equation x² + (-4)x + (0) = 0.
Explanation
Explanation
We need two numbers whose sum is 4 and product is 0 (since for x² + bx + c, sum of roots = -b, product = c). Those numbers are 0 and 4, so the equation factors as (x - (0))(x - (4)) = 0, giving x = 0 or x = 4.
PRO TIP
Re-check your working by substituting the answer back into the original question.