Here, I'll do the first one for you. When they are talking about a number, use "x". Since it says twice a number, you say 2x. Or 3x for three times the number 2x+12=3x-31 Then use algebra to find x. Get the numbers on one side and all the x's on the other. 2x+12+31=3x-31+31 2x+43-2x=3x-2x x=43
