Question 361751
You need to have two equations that relate the length and the width independently.
Example,
Three times the width plus the length equals 10 and The width minus the length equals two.
.
.
{{{3W+L=10}}}
{{{W-L=2}}}
If you add the equations,
{{{3W+L+W-L=10+2}}}
{{{4W=12}}}
{{{W=3}}} and {{{3(3)+L=10}}}
{{{L=1}}}