I need a step by step on graphing…

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Asum and one addend are written in the triangle write the other addend then write an addition fact and a related subtraction fact for the numbers

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. the drive is currently serving a request at cylinder 2,150, and the previous request was at cylinder 1,805. the queue of pending requests, in fifo order, is: 2069, 1212, 2296, 2800, 544, 1618, 356, 1523, 4965, 3681