Question

How to solve this?

70 = -5t^2+20t+50?


the answer is 2 but i am getting 1 ?

Answer 1

hi,
divide the whole by 5 first...
14 = -t^2 + 4t + 10
now...
t^2 -4t + 4 = 0
now this is a complete square..
(t - 2)^2 = 0

now did u get it ?

Answer 2

I get it but I am trying to find the x value for teh vertex when the y value is 70

Answer 3

So How can I solve for t algebraically?

Answer 4

show ur steps.... then we can tell ya wt's wrong with them... that way u'll understand it better

Answer 5

I dont even know how to start?

Answer 6

but ya said that ya get 1 instead of 2 ?

Answer 7

70=-5(t^2-4t-10)

Answer 8

ya basically wants to find the value of t when y = 70 am I right ?

Answer 9

yea

Answer 10

How can I do that?

Answer 11

I got it, I have to complete the square which gives me -5(t-2)^2-20

and then I can set t-2 = 0 and then t = 2 which is the correct answer

Answer 12

yep!! ya got it man

Answer 13

i was just about to suggest that!