Question 847821
Numbers a and b, {{{a<b}}}.

{{{b-a=16}}} and {{{a+b=-6+3a}}}; in other words, you start with two equations.


Simplify the a+b equation.
{{{a+b-3a=-6}}}
{{{-2a+b=-6}}}
{{{highlight_green(2a-b=6)}}}.


Put the a-b equation into the same form.
{{{-a+b=16}}}
{{{highlight_green(a-b=-16)}}}.


You could have skipped most of that once you had the two equations translated from the description, and then continued with a substitution method to find a and b; but now you also have an equivalent system of equations for which the Elimination Method would be convenient.

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Subtract one equation from the other to eliminate b:
{{{2a-b-(a-b)=6-(-16)}}}
... which will give you.....?