How do i solve this? (answer is k.)

The polygon tool to draw a rectangle with a length of 5 units and a height of 3 units. one of the sides of the rectangle falls on line ab , and the rectangle has a vertex of a. each segment on the grid represents 1 unit.

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?

What are the solutions of the system? solve by graphing. y = x^2 + 3x + 2 y = 2x + 2