a) Evaluate the given function at each value of x. We have f(x) = 2x + 3.
• If x = -2, then
f(-2) = 2 (-2) + 3 = -4 + 3 = -1
• If x = -1, then
f(-1) = 2 (-1) + 3 = -2 + 3 = 1
• If x = 0, then
f(0) = 2 (0) + 3 = 0 + 3 = 3
and so on.
b) Kind of a silly question. Of course f(x) is a function, the instructions for part (a) say so!
But the real reason f(x) is indeed a function is that no single value of x returns more than one value of f(x).
