Question 1130672

{{{3y + x = 1}}}
{{{y= -(1/3) x + 1/3}}}
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{{{x + 3y= 1}}}
{{{(1/3) x+y= 1/3}}}


*[invoke solving_linear_system_by_substitution 1, 3, 1, "1/3", 1, "1/3"]