The piece of paper has 4 corners. If you cut 2 in.^2 from each corner, you are taking out 8 in.^2 of area. The area of the uncut sheet is 8.5 in. * 11 in. = 93.5 in.^2 93.5 in.^2 - 8 in.^2 = 85.5 in.^2
M will represent Matt and J is Jackson. M-2.25=J. You minus the difference between them and show that it equals to Jacksons. A variable is a number in math that can vary.