Answer
$x=5$
$y=2$
Work Step by Step
#$1$
The first step to solving systems of equations by substitution is to get one equation equal to one variable. This is more easily done in the first equation by subtracting 3 and 3y from both sides of the equation. Then simplify the second equation for easier substitution later by dividing by the greatest common multiple on both sides of the equation.
$y=x-3$
$x+2y=9$
#$2$
The next step is to substitute y for its equivalent and then solve for the only remaining variable, x.
$x+2(x-3)=9$
$x + 2x-6=9$
$3x-6=9$
.......+6 .....+6
$3x=15$
$3x\div3=15\div3$
$x=5$
#$3$
Substitute value of x into 1st or 2nd equation.
We use first equation to solve for y.
$y= 5 - 3$
$y=2$
#$4$
The answer is $x=5$ , $y=2$
