Help it’s 8th grade eek

The length of a rectangle plus its width is 24 cm. the area is 143 square cm. what are the length and width of the rectangle?

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

Hi i’m not sure how to do question 20 if u could explain how to do it that’d b great