Question

cần gấp ạ

Answer 1

Bài 2.

a)

$\dfrac{5}{x^2-1} : \dfrac{x^2+2x+3}{x+1}$

$=\dfrac{5}{x^2-1}\cdot\dfrac{x+1}{x^2+2x+3}$

$=\dfrac{5(x+1)}{(x-1)(x+1)(x^2+2x+3)}$

$=\dfrac{5}{(x-1)(x^2+2x+3)}$

b)

$\dfrac{15(x+1)^2}{x^2-9} : \dfrac{x^2+2x+1}{x+3}$

$=\dfrac{15(x+1)^2}{(x-3)(x+3)}\cdot\dfrac{x+3}{(x+1)^2}$

$=\dfrac{15}{x-3}$

c)

$\dfrac{-2x}{y^4-16} : \dfrac{1}{y^2+4}$

$=\dfrac{-2x}{(y^2-4)(y^2+4)}\cdot(y^2+4)$

$=\dfrac{-2x}{y^2-4}$

d)

$\dfrac{-2x}{x^3-8} : \dfrac{4x}{x^2+2x+4}$

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

$=\dfrac{-2}{4(x-2)}$

$=\dfrac{-1}{2(x-2)}$

Answer 2

Bài 3

a)

$M\cdot\dfrac{x+1}{2x+1}=\dfrac{x^2+x}{4x^2-1}$

$M=\dfrac{x^2+x}{4x^2-1}\cdot\dfrac{2x+1}{x+1}$

$=\dfrac{x(x+1)}{(2x-1)(2x+1)}\cdot\dfrac{2x+1}{x+1}$

$=\dfrac{x}{2x-1}$

b)

$M\cdot\dfrac{y^2+2y}{9y^2-1}=\dfrac{y+2}{3y+1}$

$M=\dfrac{y+2}{3y+1}\cdot\dfrac{9y^2-1}{y^2+2y}$

$=\dfrac{y+2}{3y+1}\cdot\dfrac{(3y-1)(3y+1)}{y(y+2)}$

$=\dfrac{3y-1}{y}$

c)

$\dfrac{2xy}{x+1}\cdot M=\dfrac{2x^2y}{x^2-1}$

$M=\dfrac{2x^2y}{x^2-1}\cdot\dfrac{x+1}{2xy}$

$=\dfrac{x(x+1)}{(x-1)(x+1)}$

$=\dfrac{x}{x-1}$