Question 144159
Start with the given system

{{{8x-7y=12}}}
{{{y=x+3}}}




{{{8x-7(x+3)=12}}}  Plug in {{{y=x+3}}} into the first equation. In other words, replace each {{{y}}} with {{{x+3}}}. Notice we've eliminated the {{{y}}} variables. So we now have a simple equation with one unknown.



{{{8x-7x-21=12}}} Distribute



{{{x-21=12}}} Combine like terms on the left side



{{{x=12+21}}}Add 21 to both sides



{{{x=33}}} Combine like terms on the right side





Now that we know that {{{x=33}}}, we can plug this into {{{y=x+3}}} to find {{{y}}}




{{{y=(33)+3}}} Substitute {{{33}}} for each {{{x}}}



{{{y=36}}} Simplify



So our answers are {{{x=33}}} and {{{y=36}}}