Question

5+а⁴+a; (a-b) (a+b) ;7x³y 1,5x²y​

Answer 1

1. Не знаю, может там ошибка

$5 + {a}^{4} + a =$

2.

$(a - b)(a + b) = {a}^{2} - {b}^{2}$

3.

$7x {}^{3} y \times 1.5x {}^{2} y = 10.5x {}^{3 + 2} y {}^{1} \times y {}^{1} = 10.5x {}^{5} y {}^{1 + 1} = 10.5 {x}^{5} {y}^{2}$