Question

GUYS HELPAHHH!!

Anyway can anyone explain how to do 12. (a
Just letter a
Thanksss

Answer 1

x = 3 seconds

Explanation:

The time (x) at which the function
`-(x-3)^2+23` reaches its maximum can be determined in couple of ways. If you know calculus, you differentiate the quadratic, set to 0 and solve:
`y'= -2(x-3)=0 \implies x=3`. If you do not yet know how to do that, you can just apply the following argument:

The expression
`-(x-3)^2` will be non-positive for any x. The largest it can be is 0. So the entire function
`-(x-3)^2+23` can be at most 23, or less. It is 23 only when
`-(x-3)^2=0` and that happens exactly for x=3 (seconds).

As a third option, you can also use a formula for the maximum point of a parabola, but the formula is non-intuitive so I prefer to skip that.