Graph the equation x + 3y = 7. | |
With all equations, it is really up you which variable to solve for, but for this problem it would be easiest to solve for x, since it doesn't have a coefficient.  | |  | subtract 3y from each side |  | simplify |
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Now, let's plug in some numbers for y and solve for x. | y | x = 7 – 3y | (x, y) |  | x = 7 – 3(0)
x = 7 – 0
x = 7 | (7, 0) | | 1 | x = 7 – 3(1)
x = 7 – 3
x = 4 | (4, 1) | | 2 | x = 7 – 3(2)
x = 7 – 6
x = 1 | (1, 2) |
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Since we picked values for y and solved for x, we must be careful to plot them in the correct order, x then y. 
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