mn giúp e với ạ
a: ĐKXĐ: \(x\notin\left\{2;-2;-3\right\}\)
\(\dfrac{3x+9}{x^2-4}:\dfrac{x+3}{x-2}\)
\(=\dfrac{3\left(x+3\right)}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{x-2}{x+3}\)
\(=\dfrac{3}{x+2}\)
b: ĐKXĐ:\(x\ne\pm2y\)
\(\dfrac{5x^2+10xy}{x^2+2xy+4y^2}:\dfrac{x+2y}{x^3-8y^3}\)
\(=\dfrac{5x\left(x+2y\right)}{x^2+2xy+4y^2}\cdot\dfrac{\left(x-2y\right)\left(x^2+2xy+4y^2\right)}{x+2y}\)
\(=5x\left(x-2y\right)\)
c: ĐKXĐ: \(x\notin\left\{3;-2;-3;-1\right\}\)
\(\dfrac{x+1}{x-3}:\dfrac{x+2}{x+3}:\dfrac{x+3}{x+1}\)
\(=\dfrac{x+1}{x-3}\cdot\dfrac{x+3}{x+2}\cdot\dfrac{x+1}{x+3}\)
\(=\dfrac{\left(x+1\right)^2}{\left(x-3\right)\left(x+2\right)}\)
d: ĐKXĐ: \(x\notin\left\{0;\dfrac{1}{2}\right\}\)
\(\dfrac{4x^2+1}{x}:\left(1-2x\right)\)
\(=\dfrac{4x^2+1}{x\cdot\left(1-2x\right)}\)
\(=\dfrac{4x^2+1}{x-2x^2}\)