How do we keep an equation balanced while we solve for the variable

Moira has a canvas that is 8 inches by 10 inches. she wants to paint a line diagonally from the top left corner to the bottom right corner. approximately how long will the diagonal line be?

How many solutions does the nonlinear system of equations graphed below have? a. one b. zero c. four d. two

Tom drove 206 miles in 3.9 hours. estimate his average speed.