The maximum height is given by the h coordinate of the vertex of the parabola. To find this you need to find the t coordinate.You can find the t coordinate (or the time to reach max h, part B) by using the formula -b/2a, where b is the t coefficient (or 35 in this case) and a is the t^2 coefficient (or -5). So the time to reach the maximum height (units along the t-axis) is:-35/(2*-5), or 7/2 time units. Then find the maximum height by plugging this t-value into the equation and solving for h(7/2).To find how long it takes to hit the ground, solve for when t=0. This equation isn't easily factored, so use the quadratic formula. You'll want the largest t value, of the two, or the nonnegative value.