(2a+1)^2+2(2a+1)(a-1)+(a-1)^2 при a= -3,5 (с решением)

Решите задачу:

$(2 \times ( - 3.5) + 1 {)}^{2} + 2(2 \times ( - 3.5) + 1) \times ( - 3.5 - 1) + ( - 3.5 - 1 {)}^{2} = \\ = ( - 7 + 1 {)}^{2} + 2( - 7 + 1) \times ( - 4.5) - ( - 4.5 {)}^{2} = \\ = ( - 6 {)}^{2} + 2 \times ( - 6) \times ( - 4.5) + ( - \frac{9}{2} {)}^{2} = \\ = 36 + 54 + \frac{81}{4} = \\ = 90 + \frac{81}{4} = \frac{441}{4} = 110 \frac{1}{4}$