Let's write in expanded form: <math><msup><mrow><mo>(</mo><mi>a</mi><mo> + </mo><mi>b</mi><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msup></math>
 <math><mo>(</mo><mi>a</mi><mo> + </mo><mi>b</mi><mo>)</mo><mo>·</mo><mo>(</mo><mi>a</mi><mo> + </mo><mi>b</mi><mo>)</mo></math>
 <math></text><text><mi>a</mi><mo>·</mo><mi>a</mi></text><text><mo> + </mo><mi>a</mi><mo>·</mo><mi>b</mi></text><text><mo> + </mo><mi>b</mi><mo>·</mo><mi>a</mi></text><text><mo> + </mo><mi>b</mi><mo>·</mo><mi>b</mi></text><text></math>

▷<b>Answer: &nbsp; <math><msup><mrow><mi>a</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> + </mo><mn>2</mn><mi>a</mi><mo>·</mo><mi>b</mi><mo> + </mo><msup><mrow><mi>b</mi></mrow><mrow><mn>2</mn></mrow></msup></math></b><span style='font-size:smaller'> &nbsp; &nbsp; (computation took 3 steps and 0 ms)</span>