Question

rút gọn phân thức:

a, -3x+3y/x-y

b,2x^2+5x+2/2x^3+9x^2+12x+4

c, x^3+2x^2-x-2/x^3-3x+2

Answer 1

a: \(=\dfrac{-3\left(x-y\right)}{x-y}=-3\)

b: \(=\dfrac{2x^2+4x+x+2}{2x^3+x^2+8x^2+8x+4x+4}\)

\(=\dfrac{\left(x+2\right)\left(2x+1\right)}{\left(2x+1\right)\left(x^2+8x+4\right)}=\dfrac{x+2}{x^2+8x+4}\)

c: \(=\dfrac{\left(x+2\right)\left(x^2-1\right)}{x^3-x-2x+2}\)

\(=\dfrac{\left(x+2\right)\left(x-1\right)\left(x+1\right)}{x\left(x-1\right)\left(x+1\right)-2\left(x-1\right)}\)

\(=\dfrac{\left(x+2\right)\left(x-1\right)\left(x+1\right)}{\left(x-1\right)\left(x^2+x-2\right)}\)

\(=\dfrac{\left(x+2\right)\left(x+1\right)}{\left(x+2\right)\left(x-1\right)}=\dfrac{x+1}{x-1}\)