Question 1205753


{{{-3x+5y=21}}}......eq.1.....both sides multiply by {{{2}}}
{{{6x-y=-15}}}........eq.2
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{{{-6x+10y=42}}}......eq.1
{{{6x-y=-15}}}........eq.2
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{{{-6x+10y+6x-y=42-15}}}

{{{9y=27}}}

{{{y=3}}}

go to

{{{6x-y=-15}}}........eq.2, substitute {{{y}}}

{{{6x-3=-15}}}

{{{6x=-15+3}}}

{{{6x=-12}}}

{{{x=-2}}}