To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $x-7$ and $7-x$ is $x-7$. Multiply $\frac{x}{7-x}$ times $\frac{-1}{-1}$.
$$\frac{x+7}{x-7}-\frac{-x}{x-7}$$
Since $\frac{x+7}{x-7}$ and $\frac{-x}{x-7}$ 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 $x-7$ and $7-x$ is $x-7$. Multiply $\frac{x}{7-x}$ times $\frac{-1}{-1}$.
$$\frac{x+7}{x-7}-\frac{-x}{x-7}$$
Since $\frac{x+7}{x-7}$ and $\frac{-x}{x-7}$ have the same denominator, subtract them by subtracting their numerators.
