Answer:
Explanation:
Choice B is correct. It’s given that the helicopter’s initial height is 40 feet above the ground and that when the helicopter’s altitude begins to increase, it increases at a rate of 21 feet per second. Therefore, the altitude gain t seconds after the helicopter begins rising is represented by the expression 21 t. Adding this expression to the helicopter’s initial height gives the helicopter’s altitude above the ground y, in feet, t seconds after the helicopter begins to gain altitude: y equals, 40 plus 21 t.