y = 4x +1 is an equation that represents a function. When you input values for x ... f(x) = 4x + 1, find f(2). You read this problem like this: “given f of x equals 4x plus one, find f of 2. ... output of 9.f(x) = 4x + 1. f(2) = 4(2) + 1 = 8 + 1 = 9.
