Let's simplify: <math><mfrac><mrow><mn>9</mn><mi>x</mi></mrow><mrow><mn>-3</mn></mrow></mfrac></math>
 <math><mo>-</mo><mfrac><mrow><mn>9</mn><mi>x</mi></mrow><mrow><mn>3</mn></mrow></mfrac></math>

▷<b>Result: &nbsp; <math><mo>-</mo><mn>3</mn><mi>x</mi></math></b><span style='font-size:smaller'> &nbsp; &nbsp; (computation took 2 steps and 1 ms)</span>