Question 1081861
{{{(x+y)+(y+z)+(z+x)=12+10+8}}}


{{{2x+2y+2z=30}}}


{{{x+y+z=15}}}


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{{{x+y+z-(y+z)=15-10}}}
{{{x=5}}}
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{{{x+y+z-(x+z)=15-8}}}
{{{y=7}}}
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{{{x+y+z-(x+y)=15-12}}}
{{{z=3}}}
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SOLUTION:   {{{system(x=5,y=7,z=3)}}}