Let's differentiate: <math><mo>(</mo><mn>3</mn><msup><mrow><mi>x</mi></mrow><mrow><mn>5</mn></mrow></msup><mo>)'</mo></math>
 <math><mn>3</mn><mo>·</mo><mn>5</mn><msup><mrow><mi>x</mi></mrow><mrow><mn>4</mn></mrow></msup></math>

▷<b>Result: &nbsp; <math><mn>15</mn><msup><mrow><mi>x</mi></mrow><mrow><mn>4</mn></mrow></msup></math></b><span style='font-size:smaller'> &nbsp; &nbsp; (computation took 2 steps and 2 ms)</span>