1/5( 5/2 x 4/7 -11/7) + 3/28
Multiply the terms (5/2 x 4/7) in bracket then subtract it from 11/14. Result will be 10/7.
Then multiply 1/5 with 10/7. The result will be 2/7.
2/7 + 3/28 = 11/28
T
When x equals 14 y is 168
A graphing calculator shows the time to be 7.884 seconds.
_____
The quadratic formula tells you the time is
.. t = (-12 -√(12^2 +4*16*900))/(-32) = (3/8)*(1 +√401) . . . seconds