Which of these values for P and a will cause the function f(x)=Pa^x to be an exponential growth function?

The base of a triangle exceeds the height by 7 centimeters. if the area is 400 square centimeters, find the length of the base and the height of the triangle.

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)