Use a different color pen to draw a vertical line through x = 1 on the x axis. See the attached image and you'll see I'm drawing a vertical red line. This red line crosses the slanted black line at the location (1,-2), which is the blue point marked. The x coordinate of this point is x = 1 and the y coordinate of this point is y = -2.
So when x = 1, the value of y is y = -2 which is the final answer