Answer:
t = -1 or 5/2
Step-by-step explanation:
To find t; we equate H(t) = 0
-16t^2+24t+40.0= 0
dividing through by 8 we have ;
-16t^2 / 8+ 24t/8+40.0/8=0
-2t^2 + 3t + 5=0
-2t^2 + 5t -2t + 5=0
By factorisation;
t(-2t + 5) +1 (-2t + 5)=0
This means;
(t + 1)(-2t +5)= 0
t + 1 = 0 or -2t + 5 = 0;
t= -1 ; -2t = -5
2t = 5
t = 5/2;
Hence t = -1 or 5/2
