After solving -4x -12 = 4x + 12, you get 8x = 0, what is the answer?

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?

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?

Can someone answer this question for me