Locate 1 on the x axis. This is the horizontal number line.
Draw a vertical line through 1 on the x axis. Extend this vertical line as far up and down as you can.
Notice how the vertical line crosses the blue curve. Mark this point. Then draw a horizontal line from this point to the y axis. The horizontal line will touch -4 on the y axis. So that means the point (1,-4) is on the curve.
If the input it is x = 1, then the output is y = -4
