Which of the following expressions is a common factor when the expressions x2 – 9 and x2 – 5x + 6 are factored?

What percent of the circle below is shaded?

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?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'