Question 999411
Substitute with given values,
{{{A(3)+3(n)=6}}}
{{{3A+3n=6}}}
{{{A+n=2}}}
.
.
.
{{{5(n)+5=20}}}
{{{5n+5=20}}}
{{{n+1=4}}}
{{{n=3}}}
So then,
{{{A+3=2}}}
{{{A=-1}}}