Multiply both sides by \(3\).
\[x-9=9x+21\]
Subtract \(x\) from both sides.
\[-9=9x+21-x\]
Simplify \(9x+21-x\) to \(8x+21\).
\[-9=8x+21\]
Subtract \(21\) from both sides.
\[-9-21=8x\]
Simplify \(-9-21\) to \(-30\).
\[-30=8x\]
Divide both sides by \(8\).
\[-\frac{30}{8}=x\]
Simplify \(\frac{30}{8}\) to \(\frac{15}{4}\).
\[-\frac{15}{4}=x\]
Switch sides.
\[x=-\frac{15}{4}\]
Decimal Form: -3.75
x=-15/4
