Examples | Quadratic Equations | Quadratic Formula - Mathway Use the quadratic formula to find the solutions. −b±√b2 −4(ac) 2a - b ± b 2 - 4 ( a c) 2 a Substitute the values a = 1 a = 1, b = −6 b = - 6, and c = 9 c = 9 into the quadratic formula and solve for x x. 6±√(−6)2 − 4⋅(1⋅9) 2⋅1 6 ± ( - 6) 2 - 4 ⋅ ( 1 ⋅ 9) 2 ⋅ 1 Simplify. Tap for more steps... x = 3 x = 3