Question 493725
Given the quadratic function f(x) = x2 – 18x + 81, find a value of x such that f(x) = 16
.
substitute in the value of f(x):
f(x) = x^2 – 18x + 81
16 = x^2 – 18x + 81
0 = x^2 – 18x + 65
factoring:
0 = (x-5)(x-13)
x = {5, 13}  (two possible solutions)