0=65-10t-5t^2
now what you want to do is multiply a and c
-5(t^2+2t-13)
Now just find the zeros
1+2=3. 4/10+2/10=6/10. 3+ 6/10=3 6/10
for one show it will be 23.1 minutes if you multiply 2.30 minutes by 3 and get 6.9 you subtract 6.9 from the 30 minutes and you should 23.1 minutes
