Answer:
(x, y) = (4, 16)
Step-by-step explanation:
The first equation is a proportion, so you know right away that (0, 0) is on the graph. Pick any value you like for x, and y will be 4 times that. So, for example, the point (5, 20) will also be on the graph of y=4x.
The second equation has a y-intercept of 20 and a slope of -1. So, however many unit to the right of the y-axis you choose to go, the y-value will be down that number of units from 20. In addition to (0, 20), the point (5, 15) will be on the graph of y = -x+20.
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Personally, I like to use a graphing calculator to show the graphical solution.
Here, the solution is (x, y) = (4, 16).
