Question

[Trương Tiền]

Quy đồng các phân thức

A. -7\x^2-4; 11\2x+4

B. 2\9x^2-1; 4x \1-3x

C.3\x+2;x+1\x^3+8;x+2\2x+4

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(\dfrac{-7}{x^2-4}=\dfrac{-7}{\left(x-2\right)\left(x+2\right)}=\dfrac{-14}{2\left(x-2\right)\left(x+2\right)}\)

\(\dfrac{11}{2x+4}=\dfrac{11}{2\left(x+2\right)}=\dfrac{11\left(x-2\right)}{2\left(x+2\right)\left(x-2\right)}\)

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

\(\dfrac{4x}{1-3x}=\dfrac{-4x}{3x-1}=\dfrac{-4x\left(3x+1\right)}{\left(3x-1\right)\left(3x+1\right)}\)

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

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

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