To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $a-2$ and $\left(a-2\right)\left(a+1\right)$ is $\left(a-2\right)\left(a+1\right)$. Multiply $\frac{5}{a-2}$ times $\frac{a+1}{a+1}$.
Since $\frac{5\left(a+1\right)}{\left(a-2\right)\left(a+1\right)}$ and $\frac{4a}{\left(a-2\right)\left(a+1\right)}$ 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 $a-2$ and $\left(a-2\right)\left(a+1\right)$ is $\left(a-2\right)\left(a+1\right)$. Multiply $\frac{5}{a-2}$ times $\frac{a+1}{a+1}$.
Since $\frac{5\left(a+1\right)}{\left(a-2\right)\left(a+1\right)}$ and $\frac{4a}{\left(a-2\right)\left(a+1\right)}$ have the same denominator, subtract them by subtracting their numerators.
