To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $\left(x-2\right)\left(x+2\right)$ and $\left(x-2\right)^{2}$ is $\left(x+2\right)\left(x-2\right)^{2}$. Multiply $\frac{3}{\left(x-2\right)\left(x+2\right)}$ times $\frac{x-2}{x-2}$. Multiply $\frac{2}{\left(x-2\right)^{2}}$ times $\frac{x+2}{x+2}$.
Since $\frac{3\left(x-2\right)}{\left(x+2\right)\left(x-2\right)^{2}}$ and $\frac{2\left(x+2\right)}{\left(x+2\right)\left(x-2\right)^{2}}$ have the same denominator, subtract them by subtracting their numerators.
Divide $\frac{x-10}{\left(x+2\right)\left(x-2\right)^{2}}$ by $\frac{2x-20}{3x^{2}-12}$ by multiplying $\frac{x-10}{\left(x+2\right)\left(x-2\right)^{2}}$ by the reciprocal of $\frac{2x-20}{3x^{2}-12}$.
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $\left(x-2\right)\left(x+2\right)$ and $\left(x-2\right)^{2}$ is $\left(x+2\right)\left(x-2\right)^{2}$. Multiply $\frac{3}{\left(x-2\right)\left(x+2\right)}$ times $\frac{x-2}{x-2}$. Multiply $\frac{2}{\left(x-2\right)^{2}}$ times $\frac{x+2}{x+2}$.
Since $\frac{3\left(x-2\right)}{\left(x+2\right)\left(x-2\right)^{2}}$ and $\frac{2\left(x+2\right)}{\left(x+2\right)\left(x-2\right)^{2}}$ have the same denominator, subtract them by subtracting their numerators.
Divide $\frac{x-10}{\left(x+2\right)\left(x-2\right)^{2}}$ by $\frac{2x-20}{3x^{2}-12}$ by multiplying $\frac{x-10}{\left(x+2\right)\left(x-2\right)^{2}}$ by the reciprocal of $\frac{2x-20}{3x^{2}-12}$.