Question 1095906
k, Ken
L, Laura
{{{system(k=L-21,(L-3)=2(k-3))}}}

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{{{L-3=2(L-21-3)}}}
{{{L-3=2L-48}}}
{{{-3+48=L}}}
{{{L=45}}}
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{{{k=45-21}}}
{{{highlight(k=24)}}}
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and you also know {{{L=45}}}.