Question

Помогите пожалуйста ​

Answer 1

$a {(a + b)}^{2} + 2a( {a}^{2} + {b}^{2} ) - a {(a - b)}^{2} = a( {a}^{2} + 2ab + {b}^{2} ) + 2 {a}^{3} + 2a {b}^{2} - \\ \\ - a( {a}^{2} - 2ab + {b}^{2} ) = {a}^{3} + 2 {a}^{2} b + a {b}^{2} + 2 {a}^{3} + 2a {b}^{2} - {a}^{3} + 2 {a}^{2} b - a {b}^{2} = \\ \\ = 2 {a}^{3} + 4 {a}^{2} b + 2a {b}^{2} = 2a( {a}^{2} + 2ab + {b}^{2} ) = 2a {(a + b)}^{2} = 2 \times 2.5 \times {(2.5 + 0.5)}^{2} = \\ \\ = 5 \times 9 = 45$