Question

What i sthe range of the quadratic function F(x)= -5x^2+30x+4
A.) Y<49
B.) Y<3
C.) x>49
D.) Y>49

Answer 1

Range is valid set of x values while domain is y. So immediately C is ruled out. We can see that as x grows, this function goes very negative. In fact, infinitely so. We now need the max. We can get this with the first derivative and setting it equal to 0. So we get the max value is y=49. So it goes from 49 down, or A.

Answer 2

If in doubt, you can always graph it.