h=at-.25vtsquared ,solve for a

Please help me, I have no idea how to solve!

We try to isolate the target variable a on the left hand side of the equation.

h=at-(1/4)vt²
h-at = at-at -(1/4)vt² (subtract at on each side)
h-at = -(1/4)vt²
h-h -at = -(1/4)vt² -h (subtract h on each side)
-at = -(1/4)vt²-h
Now divide by -t on each side
-at/(-t) = (-(1/4)vt²-h)/(-t)
a = ((1/4)vt²+h)/t
=(1/4)vt + h/t