3x + 2y = 13
y = x - 1
We want to substitute the second equation into the first equation.
In the first equation, everytime we see "y" substitute x-1
3x +2y = 13
3x + 2( x-1) = 13
Distribute
3x +2x -2 = 13
Combine like terms
5x -2 = 13
Add 2 to each side
5x-2+2 = 13+2
5x = 15
Divide each side by 5
5x/5 = 15/5
x = 3
Noe we can find the value of y by using the second equation
y = x-1
y = 3-1
y =2
The solution is
( 3,2)