Question

(y + 9)(y - 2) + (3 - y)(6 + 5y) , якшо y = - 1 1/2

Answer 1

$(y + 9)(y - 2) + (3 - y)(6 + 5y) = {y}^{2} - 2y + 9y - 18 + 18 + 15y - 6y - {5y}^{2} = - {4y}^{2} + 16y$

$- 1 \frac{1}{2} = - \frac{3}{2}$

${ - 4y}^{2} + 16y = - 4 \times {( - \frac{3}{2}) }^{2} + 16 \times ( - \frac{3}{2} ) = - \frac{4}{1} \times \frac{9}{4} + \frac{16}{1} \times ( - \frac{3}{2} ) = - 9 + ( - 24) = - 9 - 24 = - 33$