Question 198012
{{{12x - 7y = -10}}}
{{{-4x + 3y = 10}}}
Multiply both sides of the 2nd equation by {{{3}}}
and add the equations
{{{12x - 7y = -10}}}
{{{-12x + 9y = 30}}}
--------------------
{{{2y = 20}}}
{{{y = 10}}}
Plug this result back in to 2nd equation
{{{-4x + 3y = 10}}}
{{{-4x + 3*10 = 10}}}
{{{-4x = 10 - 30}}}
{{{-4x = -20}}}
{{{x = 5}}}
The solution is {{{x = 5}}},{{{y = 10}}}
check:
{{{12*5 - 7*10 = -10}}}
{{{60 - 70 = -10}}}
{{{-10 = -10}}}
and
{{{-4*5 + 3*10 = 10}}}
{{{-20 + 30 = 10}}}
{{{10 = 10}}}
OK