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How do you do this 10x-7=y
3y+9=x

User Msridhar
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1 Answer

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\left \{ {{10x-7=y} \atop {3y+9=x}} \right. \\\\substitution\ method\\\\10(3y+9)-7=y\\\\ 30y+90-7=y\\\\ 30y+83=y\ \ \ \ | subtract\ 30y\\\\ 83=-29y\ \ \ | divide\ by\ -29\\\\ y=-(83)/(29)\\\\ x=3y+9=3*(-(83)/(29))+9=(178)/(29)
User TOPKAT
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