What is the formula of surface area of cone and surface area of hemisphere

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

Thee blue triangle has rotated from quadrant i to quadrant iii about the origin. describe the effects of the rotation on the coordinates of the blue triangle.

Kendra had twice as much money as kareem. kendra later spent $8 and kareem earned $6. by then, the two had the same amount of money. how much money did each have originally?