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| Math Central | Quandaries & Queries |
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Question from Susan, a parent: (28x + 36y) - [20000 - .75(28x + 36y) + 60000] = 5000 |
Hi Susan,
I would begin by simplifying the first equation
\[(28x + 36y) - [20000 - .75(28x + 36y) + 60000] = (28x + 36y) - 20000 + \frac34 (28x + 36y) - 60000 \]
and hence the first equation can be written
\[\frac74 (28x + 36y) = 49x + 63y = 85000.\]
Solve the second equation, $x + y = 10000$ for $y$ and substitute into the simplified form of the first equation and solve for $x.$
Penny
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