Learn how to solve quadratic equations problems step by step online. Solve the quadratic equation x^2-4x=18. Factor the polynomial x^2-4x. Add and subtract \left(\frac{b}{2}\right)^2, replacing b by it's value -4. Now, we can factor x^2+-4x+4 as a squared binomial of the form \left(x+\frac{b}{2}\right)^2. We need to isolate the dependent variable x, we can do that by simultaneously subtracting -4 from both sides of the equation. Canceling terms on both sides.

Solve the quadratic equation x^2-4x=18