Question 686956

{{{a-15=b}}}.......eq.1

{{{3a=b-15}}}.....eq.2
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{{{3a=b-15}}}.....eq.2..substitute {{{b}}} from eq.1

{{{3a=a-15-15}}}......solve for {{{a}}}

{{{3a-a=-30}}}

{{{2a=-30}}}

{{{a=-30/2}}}

{{{highlight(a=-15)}}}

go back to eq.1 and solve for {{{b}}}

{{{a-15=b}}}.......eq.1

{{{-15-15=b}}}

{{{highlight(b=-30)}}}