Question

помогите пожалуйста срочно 14 балов,два последних

Answer 1

1)
$( frac{x + y}{x - y} - frac{x - y}{x + y} - frac{4 {y}^{2} }{ {x}^{2} - {y}^{2} } ) times frac{x + y}{2y} = frac{ {(x + y)}^{2} - {(x - y)}^{2} - 4 {y}^{2} }{(x - y)(x + y)} times frac{x + y}{2y} = frac{ (x + y + x - y)(x + y - x + y) - 4 {y}^{2} }{(x - y) times 2y} = frac{2x times 2y - 4 {y}^{2} }{2y(x - y)} = frac{4y(x - y)}{2y(x - y)} = 2$
2)
$( frac{1 - b}{1 + b} - frac{1 + b}{1 - b} + frac{1 + 4b}{1 - {b}^{2} } ) times ( {b}^{2} + 2b + 1) = frac{ {(1 - b)}^{2} - {(1 + b)}^{2} + 1 + 4b }{(1 - b)(1 + b)} times {(b + 1)}^{2} = frac{(1 - b + 1 + b)(1 - b - 1 - b) + 1 + 4b}{1 - b} times (b + 1) = frac{2 times ( - 2b) + 1 + 4b}{(1 - b)} times (b + 1) = frac{1}{1 - b} times (b + 1) = frac{1 + b}{1 - b}$