Question 164579
Let's see if {{{x=1}}} and {{{y=-3}}} satisfy the first equation.



{{{x+y=-2}}} Start with the first equation.



{{{1-3=-2}}} Plug in {{{x=1}}} and {{{y=-3}}}.



{{{-2=-2}}} Subtrac



Since the equation is <font size="4"><b>true</b></font>, this means that {{{x=1}}} and {{{y=-3}}} satisfy the first equation.



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Let's see if {{{x=1}}} and {{{y=-3}}} satisfy the second equation.



{{{x-y=4}}} Start with the second equation.



{{{(1)-(-3)=4}}} Plug in {{{x=1}}} and {{{y=-3}}}.



{{{1+3=4}}} Rewrite {{{(1)-(-3)}}} as {{{1+3}}}



{{{4=4}}} Add



Since the equation is <font size="4"><b>true</b></font>, this means that {{{x=1}}} and {{{y=-3}}} satisfy the second equation.



Since <font size="4"><b>ALL</b></font> of the equations of the system are satisfied (ie they are true for the given values) , this means that (1,-3) is a solution to the given system.




Note: a longer alternative is to solve the system (using any method) and find the true solution, which you'll find is (1,-3).