Answer
$x = 3$
$y = 2$
Work Step by Step
To solve this system of equations by substitution, you will use one equation to isolate one of the variables. In this problem, let's solve the first equation for $x$:
$x - y = 1$
To solve for $x$, you add $y$ to both sides:
$x - y + y = 1 + y$
You then get $x$ by itself:
$x = y + 1$
Now, you take what you got for the value of $x$ and plug it into the second equation:
$4(y + 1) + 3y = 18$
Distribute the terms to get:
$4y + 4 + 3y = 18$
Combine like terms:
$7y + 4 = 18$
We are trying to isolate the $y$ term now, so we subtract $4$ from each side:
$7y = 14$
To solve for $y$, we divide both sides by $7$:
$y = 2$
Now that we have the value for $y$, we can plug this value into the first equation (because it's easier than the second equation) to solve for $x$:
$x - 2 = 1$
To solve for $x$, we add $2$ to each side to get:
$x = 3$
