Question

check my parabola work?

Answer 1

s(t) = -16t^2+240t+288

Answer 2

t=7.5

Answer 3

h(t)=-16t^2+64t+21; t=2

Answer 4

c(x)=3x^2-18x+63; x=3

Answer 5

c(x)=3x^2-18x+63; c=36

Answer 6

I don;t understand what you are doing?

Answer 7

it is from word problems asking things like if you throw a ball, how many seconds until it reaches maximum height

Answer 8

i used -b/2a

Answer 9

when you throw a ball velocity at the highest point is zero;
\[v=\frac{ ds }{ dt }\]
for first
\[\frac{ ds }{ dt }=-32t+240=0,t=\frac{ 240 }{ 32 }=\frac{ 15 }{ 2 }=7.5\]
so it is correct.
similarly you can check your other answers.