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 Question from Lynn, a parent: 2x + y = 8 y + 3z =5 z + 2w =1 5w + 3x = 9 Form three equations with y eliminated

Hi Lynn,

The variable $y$ only appears in the first two equations so I want to collapse them into one equation. Since $2x + y$ is eight and $y + 3z$ is five it must be that $2x + y \mbox{ minus } y + 3z$ is $8 - 5 = 3.$ Thus

$(2x + y) - (y + 3z) = 8 - 5 = 3.$

This becomes

$2x + y - y - 3z = 3,$

or

$2x - 3z = 3.$

This equation together with the third and fourth equations in your problem form three equations with $y$ eliminated.

I hope this helps,
Penny

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