Question 1132373
p, Precy
a, Angelo


{{{system(a+3=3(p+3),a-1=7(p-1))}}}


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{{{system(a+3=3p+9,a-1=7p-7)}}}


{{{system(a-3p=6,a-7p=-6)}}}


{{{E1-E2}}}
{{{4p=12}}}
{{{highlight(p=3)}}}
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{{{highlight(a=15)}}}