Question

СРОЧНО ПРОРЕШАЙТЕ
ОЧЕНЬ НАДО

Answer 1

$(x + 7)(7 - x) + 5x(3 - x) = \ - (x + 7)(x - 7) + 15x - 5 {x}^{2} = \ - {x}^{2} + 49 - 5 {x}^{2} + 15x = \ - 6 {x}^{2} + 15x + 49$

$(y - 4) ^{2} - (y - 3)(y + 4) = \ {y}^{2} - 8y + 16 - {y}^{2} - y + 12 = \ - 9y + 28$

$32x - 5(x - 3) ^{2} = \ 32x - 5 {x}^{2} + 30x - 45 = \ - 5 {x}^{2} + 62x - 45$

2

$x^{3} - 4x = x( {x}^{2} - 4) = \ x(x - 2)(x + 2)$

$y {x}^{2} + 2yx + y = \ y ( {x}^{2} + 2x + 1) = y( {x + 1)}^{2}$

${x}^{2} + x - {y}^{2} - y = \ ( {x}^{2} - {y}^{2} ) + (x - y) = \ (x + y)(x - y) + (x - y) = \ (x - y)(x + y + 1)$

$9x - {x}^{3} = 0 \ x(9 - {x}^{2} ) = 0 \ x = 0 \ {x}^{2} = 9 \ x = 3 \ x = - 3$

$3 {x}^{2} + 27x = 0 \ 3x(x + 9) = 0 \ x = 0 \ x = - 9$

$2x(8 - 3 {x}^{2} ) + {(3x + {x}^{2}) }^{2} - {x}^{2} (x - 5)(x + 5) = \ 16x - 6 {x}^{3} + 9 {x}^{2} + 6 {x}^{3} + {x}^{4 } - {x}^{4} + 25 {x}^{2} \ 34 {x}^{2} + 16x$