To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $x\left(x+1\right)$ and $\left(x-2\right)\left(x+1\right)$ is $x\left(x-2\right)\left(x+1\right)$. Multiply $\frac{x+2}{x\left(x+1\right)}$ times $\frac{x-2}{x-2}$. Multiply $\frac{3}{\left(x-2\right)\left(x+1\right)}$ times $\frac{x}{x}$.
Since $\frac{\left(x+2\right)\left(x-2\right)}{x\left(x-2\right)\left(x+1\right)}$ and $\frac{3x}{x\left(x-2\right)\left(x+1\right)}$ have the same denominator, subtract them by subtracting their numerators.
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $x\left(x+1\right)$ and $\left(x-2\right)\left(x+1\right)$ is $x\left(x-2\right)\left(x+1\right)$. Multiply $\frac{x+2}{x\left(x+1\right)}$ times $\frac{x-2}{x-2}$. Multiply $\frac{3}{\left(x-2\right)\left(x+1\right)}$ times $\frac{x}{x}$.
Since $\frac{\left(x+2\right)\left(x-2\right)}{x\left(x-2\right)\left(x+1\right)}$ and $\frac{3x}{x\left(x-2\right)\left(x+1\right)}$ have the same denominator, subtract them by subtracting their numerators.
