Question

Помогите сократить!Срочно!!
9 класс

Answer 1

$( frac{a - 1}{a + 1} - frac{a {}^{3} + 1 }{ {a}^{2} - 1 } times frac{a - 1}{a {}^{2} + a + 1 }) div frac{a}{1 + a} = - frac{2}{a {}^{3} + {a}^{2} + a } : \ 1)frac{a {}^{3} + 1 }{ {a}^{2} - 1 } times frac{a - 1}{a {}^{2} + a + 1 } =frac{(a + 1)( a {}^{2} - a + 1) }{ (a - 1)(a + 1)} times frac{a - 1}{a {}^{2} + a + 1 } = frac{a {}^{2} - a + 1 }{a {}^{2} + a + 1 } \ 2) frac{a - 1}{a + 1} - frac{a {}^{2} - a + 1 }{a {}^{2} + a + 1 } = frac{(a {}^{3} - 1) - (a {}^{3} + 1)}{(a + 1)(a {}^{2} + a + 1) } = frac{ a {}^{3} - 1 - a {}^{3} - 1}{(a + 1)(a {}^{2} + a + 1) } = frac{ - 2}{(a + 1)(a {}^{2} + a + 1) } \ 3)frac{ - 2}{(a + 1)(a {}^{2} + a + 1) } div frac{a}{1 + a} = frac{ - 2}{(a + 1)(a {}^{2} + a + 1) } times frac{a + 1}{a} = frac{ - 2}{(a {}^{2} + a + 1) times a} = - frac{2}{a {}^{3} + {a}^{2} + a }$