5(a-1)-15=3(a+2)+4 help

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?

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle

The price of a car has been reduced from $19,000 to $11,590. what is the percentage decrease of the price of the car?