Question

The height h(t), in feet, of an airborne tee-shirt t seconds after being launched can be approximated by h(t)= -15t^2+120t+10, 0 12 years ago

Answer 1

so you need to find when H(t) equals 115 and at what time does it happen?

Answer 2

\[115=-15t ^{2}+120t+10\] solve thsi

Answer 3

ok yes i do

Answer 4

ok i will try now

Answer 5

I have -15t^2+120t+105=0

Answer 6

i subtract 115-10=105

Answer 7

should be -15t^2+120t-105=0 because you do 10-115=-105

Answer 8

oh ok I missed the negative sign for 105

Answer 9

ok this is how far i have gotten and i am not sure what to do next could you guide me?

Answer 10

do i need to know what two numbers multiply for 120t?

Answer 11

might be best to use the quadratic formula

Answer 12

well this how it suppose to look i think
-15t^2(t-?)(t-?)

Answer 13

\[\frac{ -b \pm \sqrt{b ^{2}-4ac} }{ 2a }\] where a=-15 b=120 and c=-105

Answer 14

ok so how you set up the math problem on here where do you go to find those type of setup?

Answer 15

equation button

Answer 16

ok

Answer 17

ok i see where 4ac you said c=105 is placed but what do i do with 4ac

Answer 18

it should look something like this\[\frac{ -120\pm \sqrt{120^{2}-4\times-15\times-105} }{ 2\times-15 }\]

Answer 19

oh ok i will try to solve this difficult problem