Is 22,18,12 a right triangle

What is the slope simplify your answer and write it as a proper fraction, improper fraction, or integer

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 8 = -6x a. –7.12, 1.12 b. 7.12, –1.12 c. 7.12, 1.12 d. –7.12, –1.12

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?