What percent of 56.25$ is 11.25$

How do you answer this question? (step by step)

Could somebody me with this radical simplification?

Isabel graphed the following system of equations. 2x – y = 6 y = -3x + 4 she came up with the solution (2,-2). what were the 3 steps she did to get that solution? (make sure they are in the correct order)