I dont understand it help me please

If a baseball player hits a baseball from 4 feet off the ground with an initial velocity of 64 feet per second, how long will it take the baseball to hit the ground? use the equation h = −16t2 + 64t + 4.

The acceleration of an object due to gravity is 32 feet per second squared. what is acceleration due to gravity in inches per second squared?

What is the value of x in the equation7x+2y=48 when y=3