Question

решите 16.6 под 4 5 6

Answer 1

$4) {(y + 7)}^{2} + (y+ 2)(y - 7) = {y}^{2} + 14y + 49 + {y}^{2} - 7y + 2y - 14 = {2y}^{2} + 9y + 35$
$5)(a + 1)(a - 1) - {(a + 4)}^{2} = {a}^{2} - 1 - ( {a}^{2} + 8a + 16) = {a}^{2} - 1 - {a}^{2} - 8a - 16 = - 17 - 8a$
$6)(x - 10)(9 - x) + {(x + 10)}^{2} = 9x - {x}^{2} - 90x + 10x + {x}^{2} + 20x + 100 = 39x + 10$