Rosa can paint a room in 12 hours. hanna can paint the same room in 9 hours. how long does it take for both rosa and hanna to paint the room if they are working together?

A80-foot piece of siding is cut into three pieces so that the second piece is four times four times as long as the first piece and the third piece is five times as long as the first piece. if x represents the length of the first piece, find the lengths of all three pieces.

41/17 as a decimal rounded to the nearest hundredth

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?