Please someone help me I need help ASAP. The question and answer choices are in the image

What is the first step of an indirect proof of a number that is divisible by two

We just started the introduction into circles and i have no idea how to do this.

A)a square brown tarp has a square green patch green in the corner the side length of the tarp is (x + 8) and the side length of the patch is x what is the area of the brown part of the tarpb)a square red placemat has a gold square in the corner the side length of the gold square is (x - 2) inches with the width of the red region is 4 in what is the area of the red part of the placemat