Locate -1 on the x axis. The x axis is the horizontal number line at the center of the image.
After finding -1 on the x axis, draw a vertical line as far up and down as you can on the page.
This vertical line will cross the diagonal line, which then you'll move horizontally to the y axis until you reach 3. This means the point (-1,3) is on the diagonal line. The first coordinate is x and the second is y.
So if the input is x = -1 then the output is y = 3
The output of the function is 3
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Answer: 3
