Which expressions are equivalent to 9^x

What number should be added to both sides of the equation to complete this square? x^2-10x=7

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.