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 Question from Susan, a parent: (28x + 36y) - [20000 - .75(28x + 36y) + 60000] = 5000 x + y = 10000 solving two equations involving variables

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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