Question

помогите пожалуйста!​

Answer 1

${(4 - y)}^{2} - y(y + 1) = 16 - 8y + {y}^{2} - {y}^{2} - y = 16 - 9y = 16 - 9 \times ( - \frac{1}{9} ) = \\= 16 + 1 = 17$