The maximum value of quadratic function
is at vertex of its parabola.
The maximum value of f(x) = ax² + bx + c is k at x=h
where:
and k = f(h)
We have t instead of x so it's quadratic function named h with the variable t.
So, the function gets the maximum of k at t=h₁
h(t) = -16x² + 70x + 7 ⇒ a = -16, b = 40
![h_1=(-40)/(2\cdot(-16))=(40)/(32)=\frac54](https://img.qammunity.org/2023/formulas/mathematics/high-school/sycw75jop34si55ij7ukskok4guu4jjjoe.png)
It will take 1.25 s for the rocket to reach its maximum height.
![h(h_1)=-16\cdot\left(\frac54\right)^2+40\cdot\left(\frac54\right)+7=-16\cdot(25)/(16)+50+7=-25+57=32](https://img.qammunity.org/2023/formulas/mathematics/high-school/22flr4sova2jmw2mmyn64x1gff8n05bm43.png)
The maximum height is 32 feet.