What would f(2)= be and how would you find f(x)=-65 when x =? I got the other ones but I do not understand this.

f(x) = x² - 2x - 80
f(2) = 2² - 2(2) - 80
f(2) = 4 - 4 - 80 = -80
x² - 2x - 80 = - 65
x² - 2x - 80 + 65 = 0
x² - 2x - 15 = 0
(x - 5)(x + 3)= 0
x = 5; x = -3