Question 171272
The second equation is already solved in terms of {{{x}}}, so you can just take the expression in {{{y}}} to which {{{x}}} is equal and substitute that expression for {{{x}}} in the first equation.  This gives you a single equation in a single variable:


{{{cartoon(4*red(x)+3y=9, 4*red((3y+6))+3y=9)}}}


Solve {{{4(3y+6)+3y=9)}}} for {{{y}}}.  Once you have determined the value for {{{y}}}, substitute that value into the second equation and do the arithmetic to determine the value of {{{x}}}.


To check your answers, substitute the values for {{{x}}} and {{{y}}} into both equations and verify that the result is a pair of true statements.