Ihave no clue how to get the answer or how every step goes to

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.

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers

Which is the focus of a parabola with equation y2=4x