Quadratic equations' roots are the values of the variables that satisfy the equation. They're also known as the quadratic equation's “solutions” or “zeros.” Because they satisfy the equation, the roots of the quadratic equation x² – 7x + 10 = 0 are x = 2 and x = 5. i.e., when x = 2, 22 – 7(2) + 10 = 4 – 14 + 10 = 0.