To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $\left(x-7\right)\left(x+7\right)$ and $x+7$ is $\left(x-7\right)\left(x+7\right)$. Multiply $\frac{7}{x+7}$ times $\frac{x-7}{x-7}$.
Since $\frac{3x}{\left(x-7\right)\left(x+7\right)}$ and $\frac{7\left(x-7\right)}{\left(x-7\right)\left(x+7\right)}$ have the same denominator, add them by adding their numerators.
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $x-7$ and $2\left(x+7\right)$ is $2\left(x-7\right)\left(x+7\right)$. Multiply $\frac{1}{x-7}$ times $\frac{2\left(x+7\right)}{2\left(x+7\right)}$. Multiply $\frac{7}{2\left(x+7\right)}$ times $\frac{x-7}{x-7}$.
Since $\frac{2\left(x+7\right)}{2\left(x-7\right)\left(x+7\right)}$ and $\frac{7\left(x-7\right)}{2\left(x-7\right)\left(x+7\right)}$ have the same denominator, subtract them by subtracting their numerators.
Divide $\frac{10x-49}{\left(x-7\right)\left(x+7\right)}$ by $\frac{-5x+63}{2\left(x-7\right)\left(x+7\right)}$ by multiplying $\frac{10x-49}{\left(x-7\right)\left(x+7\right)}$ by the reciprocal of $\frac{-5x+63}{2\left(x-7\right)\left(x+7\right)}$.
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $\left(x-7\right)\left(x+7\right)$ and $x+7$ is $\left(x-7\right)\left(x+7\right)$. Multiply $\frac{7}{x+7}$ times $\frac{x-7}{x-7}$.
Since $\frac{3x}{\left(x-7\right)\left(x+7\right)}$ and $\frac{7\left(x-7\right)}{\left(x-7\right)\left(x+7\right)}$ have the same denominator, add them by adding their numerators.
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $x-7$ and $2\left(x+7\right)$ is $2\left(x-7\right)\left(x+7\right)$. Multiply $\frac{1}{x-7}$ times $\frac{2\left(x+7\right)}{2\left(x+7\right)}$. Multiply $\frac{7}{2\left(x+7\right)}$ times $\frac{x-7}{x-7}$.
Since $\frac{2\left(x+7\right)}{2\left(x-7\right)\left(x+7\right)}$ and $\frac{7\left(x-7\right)}{2\left(x-7\right)\left(x+7\right)}$ have the same denominator, subtract them by subtracting their numerators.
Divide $\frac{10x-49}{\left(x-7\right)\left(x+7\right)}$ by $\frac{-5x+63}{2\left(x-7\right)\left(x+7\right)}$ by multiplying $\frac{10x-49}{\left(x-7\right)\left(x+7\right)}$ by the reciprocal of $\frac{-5x+63}{2\left(x-7\right)\left(x+7\right)}$.