What is one solution to the equation 40 = x² - 3x ?

Solve the equation 40 = x² - 3x​

---

40 = x² - 3x
x² - 3x - 40 = 0 {subtracted 40 from each side}
(x - 8)(x + 5) = 0 {factored into two binomials}
x - 8 = 0 or x + 5 = 0 {set each factor equal to zero}
x = 8 or x = -5 {solved each equation for x}

8 or -5 could each be a solution to the equation.

You could also graph the equation, with a graphing calculator, and see where it hits the x-axis.
The solutions to the equation represent the x-intercepts, because the value of y is equal to zero.

​Ask Algebra House