Question 546936
{{{-3x-4y=27}}}..............(1)
{{{5x-6y=-7}}}...............(2)

Multiply (1) by 5 and (2) by 3 and add both equations
{{{-15x-20y=135}}}
{{{15x-18y=-21}}}
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{{{-38y=114}}}
{{{-38y/-38=114/-38}}}
{{{y=-3}}}
Put the value of y in (1)
{{{-3x-4(-3)=27}}}
{{{-3x+12=27}}}
{{{-3x=27-12}}}
{{{-3x=15}}}
{{{-3x/-3=15/-3}}}
{{{x=-5}}}

(x,y)=(-5,-3)


Check
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Put the value of x and y in (1)
{{{-3x-4y=27}}}..............(1)
{{{-3(-5)-4(-3)=27}}}
{{{15+12=27}}}
{{{27=27}}}

Put the value of x and y in (2)
{{{5(-5)-6(-3)=-7}}}
{{{-25+18=-7}}}
{{{-7=-7}}}