540 men can construct a building in 7 months. how many men should be removed from work to finish the building in 9 months? ( someone explain it so that i can learn it)

Solve the system of equations. y= 2x y= x^2 - 15

Aswimming pool is a rectangle with semicircles on the end. the rectangle is 12 meters wide and 30 meters long. the diameter and width of the swimming pool are equal. sketch and label an overhead diagram of the swimming pool. find the area of the swimming pool floor.

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)