Let's solve in <math><mi>ℝ</mi></math>: <math><mn>2</mn><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>8</mn><mo> = </mo><mn>0</mn></math>
You can factorize this expression into: <math><mn>2</mn><mo>·</mo><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn><mo>)</mo><mo> = </mo><mn>0</mn></math>
Let's solve: <math><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn><mo> = </mo><mn>0</mn></math>

▷<b>Answer: &nbsp; <math><mi>x</mi><mo> = </mo><mo>{ </mo><mn>-2</mn><mo>, </mo><mn>2</mn><mo> }</mo></math></b><span style='font-size:smaller'> &nbsp; &nbsp; (processing: 3 steps, 2 ms)</span>