Question

The graph of which function will have a maximum and a y-intercept of 4?

f(x) = 4x2 + 6x – 1
f(x) = –4x2 + 8x + 5
f(x) = –x2 + 2x + 4
f(x) = x2 + 4x – 4

Answer 1

f(x) = −x^2 + 2x + 4

Reason: the leading coefficient is negative (−1), so the parabola opens downward (has a maximum), and f(0) = 4 gives the y-intercept 4.