HELP!! 5) Which number is IRRATIONAL?

A) V9

B) V27

C) V36

D) V81

In what organelle does photosynthesis take place?

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 cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).