Question

Which quadratic has a maximum?

a. y = x2 + 2x + 2
b. y = - 2x² – 3x + 5
c. y = 0.5(x – 3)2 + 1
d. y = 2x + x2 - 1

Answer 1

b. y = - 2x² – 3x + 5

Explanation:

If you check on a graphing calculator or desmos, you will see that the parabola opens down, so there is a highest point, or a maximum. You can also know that without a calculator by looking at the sign in front of x. Since answer choice b is the only one with a negative in front (meaning that the parabola opens down giving you a maximum) then you will know that that's the correct answer.