The equation to be used for this would be as follows:
h(x) = -9.8x^2 + 10x + 2
We need to find for the axis of symmetry for the time it takes to reach the maximum height and is expressed as:
x = -b/(2a)
x = -10/2(-9.8)
x = 0.51 seconds is the time it takes to reach the max. height
h(x) = -9.8x^2 + 10x + 2
h(x) = -9.8x0.51^2 + 10x0.51 + 2
h(x) = 4.55 m