PLEASE help and please show steps!!

Explain step-by-step how to simplify -5(2x – 3y + 6z – 10).

What are “like terms”? why can we only add like terms?

Adecorative window is made up of a rectangle with semicircles at either end. the ratio of ad to ab is 3: 2 and ab is 30 inches. what is the ratio of the area of the rectangle to the combined area of the semicircles? possible answers: a. 2: 3 b. 3: 2 c. 6: π d. 9: π e. 30: π