If an object is dropped from a height of 55 feet, the function d=-16t^2+55 gives the height of the object after t seconds. graph this function. approximately how long does it take the object to reach the ground (d=0)

Notice, it hits the ground when d = 0, thus 



that's when.

as far as its graph, is more or less like the picture below, now, notice that if we put the quadratic in "vertex form", it'd look like 



so its vertex is at (0, 55), so just pick one point to the left of the vertex, and one to the right of the vertex, and draw it away

The answer would be 13.5 minutes.

Aquadratic function is one of the form f(x)=ax2 + bx + c l, where a,b, and c are numbers with are not equal to zero.