c: \(\dfrac{x^3+1}{x\left(x+1\right)}=\dfrac{\left(x+1\right)\left(x^2-x+1\right)}{x\left(x+1\right)}=\dfrac{x^2-x+1}{x}\)
b: \(\dfrac{3x-3y}{2y-2x}=\dfrac{3\left(x-y\right)}{-2\left(x-y\right)}=\dfrac{3}{-2}=\dfrac{-3}{2}\)
a: \(\dfrac{3x}{2}=\dfrac{3x\cdot5y}{2\cdot5y}=\dfrac{15xy}{10y}\)