A rocket is fired upward from the ground with an initial velocity off 220 feet...

Step 1
Definition used -
Value of function at a point -
If we have to find the value of function f(x) at x =a then, We will substitute a in place of x in given function. So value of function at x = a is given by f(a).
Step 2
Given -
${\displaystyle h\left(t\right)=-16t^2+220t}$
We have to find height when t = 7
So we will substitute t = 7 in h(t)
${\displaystyle h\left(7\right)=-16{\left(7\right)}^2+220\left(7\right)=756}$ feet
Step 3
Answer - Height of rocket at t= 7 seconds is 756 feet.