Expand.
\[5x-15=3-x\]
Add \(15\) to both sides.
\[5x=3-x+15\]
Simplify \(3-x+15\) to \(18-x\).
\[5x=18-x\]
Add \(x\) to both sides.
\[5x+x=18\]
Simplify \(5x+x\) to \(6x\).
\[6x=18\]
Divide both sides by \(6\).
\[x=\frac{18}{6}\]
Simplify \(\frac{18}{6}\) to \(3\).
\[x=3\]
x=3
