how to find the x of a quadratic formula if the y=60

If y = 60, then f(x) = 60.

Since f(x)  =  2x² - 2x - 24,  60  =  2x²​ - 2x - 24

Subtracting 60 from both sides:  0  =  2x²​ - 2x - 84

Dividing both sides by 2:             0  =  x² - x - 42

Factoring:                                   0  =  (x - 7)(x + 6)

Soving for x:                               x = 7  or  x = -6