Question

bài 1: tính

a, A= 2x-9/x²-5x+6 - x+3/x-2 - 2x+1/3-x

b, B= 2x+1/x²-7x+12 - x+3/x-4 + 2x+1/x-3

c, C= x+2/x+3 - 5/x²+x-6 + 1/2-x

d, D= 3(x²+x-3)/x²+x-2 + x+3/x+2 - x-2/x-1

Answer 1

a: \(=\dfrac{2x-9}{\left(x-2\right)\left(x-3\right)}-\dfrac{x+3}{x-2}+\dfrac{2x+1}{x-3}\)

\(=\dfrac{2x-9-x^2+9+2x^2-4x+x-2}{\left(x-3\right)\left(x-2\right)}\)

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

b: \(=\dfrac{2x+1-x^2+9+2x^2-8x+x-4}{\left(x-3\right)\left(x-4\right)}\)

\(=\dfrac{x^2-5x+6}{\left(x-3\right)\left(x-4\right)}=\dfrac{x-2}{x-4}\)

c: \(=\dfrac{x^2-4-5-x-3}{\left(x-2\right)\left(x+3\right)}=\dfrac{\left(x-4\right)\left(x+3\right)}{\left(x-2\right)\left(x+3\right)}=\dfrac{x-4}{x-2}\)

d: \(=\dfrac{3x^2+3x-9+x^2+2x-3-x^2+4}{\left(x-1\right)\left(x+2\right)}\)

\(=\dfrac{3x^2+5x-8}{\left(x-1\right)\left(x+2\right)}=\dfrac{3x^2+8x-3x-8}{\left(x-1\right)\left(x+2\right)}=\dfrac{3x+8}{x+2}\)