| y | = | -2 x | - 4 |
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| y | = | 1 x | + 5 |
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| 4 |
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Once you know how to graph, solving by graphing is easy.
1—Graph the two lines.
2—See where the two lines intersect.
Here, they intersect at (-4, 4)
That point is the SOLUTION.
3—Check your answer by plugging it in to the equations.
(You have to plug it into BOTH equations, since you are checking whether it is the solution to the SYSTEM, not to just one or the other of the equations.)
| 4 | = | -2 (-4) | - 4 |
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| 4 | = | 8 | - 4 | That’s true, so (-4, 4) is a solution of the first equation |
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| 4 | = | 1 (-4) | + 5 |
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| 4 |
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| 4 | = | -1 | +5 | That’s true, so (-4, 4) is a solution of the second equation. |
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Since (-4, 4) is a solution to both equations, it is the SOLUTION of the SYSTEM.
And that is how you solve a system by graphing.
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