Question

find the maximum y-value on the graph of y=f(x).
f(x)=-x^2+8x+5

Answer 1

You know how to take derivatives?

Answer 2

nonp im so lost

Answer 3

Really? Are you in calculus?

Answer 4

MAT/117 ALGEBRA 1B

Answer 5

wow not even close haha
ok its a parabola, find vertex using
x = -b/2a

Answer 6

Ok, in that case, they don't want you to take the derivative--they want you to complete the square probably..

Answer 7

Or just use the formula provided by dumbcow....

Answer 8

Does either "Completing the Square" or "finding the vertex" sound familiar to you?

Answer 9

Because if
x=-b/(2a)
looks like something you saw in class, then use that....

Answer 10

So "sexybadass"?

Answer 11

the maximum y-value is y=

Answer 12

21

Answer 13

(If you're just looking for the answer)

Answer 14

y=21

Answer 15

Yeah, graph it and see--it occurs when x=4