Answer:
On a more detailed level, the question does not provide enough information to give an accurate answer. Polynomial functions can have many values that are called local maximums. For maximums, this means there is a lower y-value to the left and to the right of the y-value at x=3 AND a lower y-value to the left and right of the y-value at x=-1. An example of a polynomial that has maximums around x = -1 and x = 3 is -.4x^4 + 1.5x^3 + 2x^2 - 6x - 2.6. Enter this equation in your graphing calculator, then look at the table and you will see that the y-values left and right of x = -1 (f(-2) = -1 and f(0) = -2.6) are lower than f(-1) = 3.5. Same is true to the left and right of x=3 (f(2) = -1 and f(4) = -1) while f(3) = 5.5. Being able to look at the graph and the table should help you see that a function CAN have two LOCAL maximums.
