Question

Помогите срочно надо дам корону!!!к

Answer 1

$frac{3}{a} + frac{a - 3}{a + 5} = frac{3(a +5 ) + {a}^{2} - 3a}{a(a + 5)} = frac{3a - 3a + 15 + {a}^{2} }{a(a + 5)} = frac{a {}^{2} + 15 }{a(a + 5)}$

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

$frac{x + y}{y} times frac{ {x}^{2} }{ax + ay} = frac{x + y}{y} times frac{ {x}^{2} }{a(x + y)} = frac{ {x}^{2} }{ ay}$

$frac{ {a }^{2} - {b}^{2} }{b} div frac{ {a}^{2} + ab }{b} = frac{(a - b)(a + b)}{b} times frac{b}{a(a + b)} = frac{a - b}{a}$

$frac{15b}{3 - b} + frac{8b}{b {}^{2} - 9} times frac{7b + 21}{4} = frac{15b}{3 - b} + frac{8b}{(b - 3)(b + 3)} times frac{7(b + 3)}{4} = frac{15b}{3 - b} + frac{14b}{b - 3} = frac{ 15b {}^{2} - 45b - 14b {}^{2} + 42b }{ - (b - 3)(b - 3)} = frac{b {}^{2} - 3b}{ - (b - 3)(b - 3)} = frac{b(b - 3)}{- (b - 3)(b - 3)} = frac{b}{3 - b}$

$frac{2a - 2c + ax - cx}{ {x}^{2} - 4} = frac{2(a - c) + x(a - c)}{(x - 2)(x + 2)} = frac{(x + 2)(a - c)}{(x - 2)(x + 2)} = frac{a - c}{x - 2} = frac{6.7 - 3.5}{1.9 - 2} = frac{1.4}{ - 0.1} = - 14$