iúp mình vs càng nhanh càng tốt ạ
\(a,\dfrac{x}{3x+6}=\dfrac{x}{3\left(x+2\right)}=\dfrac{x\left(x+2\right)}{3\left(x+2\right)^2}\\ \dfrac{5}{x^2+4x+4}=\dfrac{5}{\left(x+2\right)^2}=\dfrac{15}{3\left(x+2\right)^2}\\ b,\dfrac{5}{x^2-y^2+2x+1}=\dfrac{5}{\left(x-y+1\right)\left(x+y+1\right)}=\dfrac{5x}{x\left(x-y+1\right)\left(x+y+1\right)}\\ \dfrac{6}{x\left(x+y+1\right)}=\dfrac{6\left(x-y+1\right)}{x\left(x-y+1\right)\left(x+y+1\right)}\)
\(c,\dfrac{7x}{x^4-1}=\dfrac{7x}{\left(x^2+1\right)\left(x-1\right)\left(x+1\right)}=\dfrac{7x\left(x^2+1\right)}{\left(x^2+1\right)\left(x-1\right)\left(x+1\right)}\\ \dfrac{5x}{x^4+2x^2+1}=\dfrac{5x}{\left(x^2+1\right)^2}=\dfrac{5x\left(x-1\right)\left(x+1\right)}{\left(x^2+1\right)^2\left(x-1\right)\left(x+1\right)}\)
