After his final exam, a student goes to the top of a building and throws his book into the air. The height h in feet of the book above the ground is given by: h = −16t 2 + 96t + 112. How long is the book in the air?

Question

After his final exam, a student goes to the top of a building and throws his book into the air. The height h in feet of the book above the ground is given by: h = −16t 2 + 96t + 112. How long is the book in the air?

anonymous · Answer

you need to make t the subject of your formula

try factorising the quadratic

amistre64 · Answer

until they hit the ground :)

amistre64 · Answer

divide out the common factors first

anonymous · Answer

can someone at least give fomula..

anonymous · Answer

1) divide through by -16 give$$h=t^2-6t-7$$  factorise: $$(x+1)(x-7)$$ so x=-1 or 7, ignore the negative value so this gives 7seconds. I am guessing on the units.