Question

1) \(\dfrac{5x+10}{4x-8}\times\dfrac{4-2x}{x+2}\)
2) \(\dfrac{1-4x^2}{x^2+4x}:\dfrac{2-4x}{3x}\)  
3) \(\dfrac{12x}{5y^3}:\dfrac{8x^3}{15y^3}\) 
4) \(\dfrac{4y^2}{11x^4}\times\left(-\dfrac{3x^2}{8y}\right)\) 
Mng giúp mk bài này với mk cần gấp. Cảm ơn bạn nhiều 

Answer 1

1: \(=\dfrac{5\left(x+2\right)}{4\left(x-2\right)}\cdot\dfrac{-2\left(x-2\right)}{x+2}=\dfrac{-10}{4}=-\dfrac{5}{2}\)

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

3: \(=\dfrac{12x}{5y^3}\cdot\dfrac{15y^3}{8x^3}=\dfrac{3\cdot3}{2x^2}=\dfrac{9}{2x^2}\)

4: \(=\dfrac{4y^2}{8y}\cdot\dfrac{-3x^2}{11x^4}=\dfrac{-3}{11x^2}\cdot\dfrac{y}{2}=\dfrac{-3y}{22x^2}\)