To add or subtract expressions, expand them to make their denominators the same. Least common multiple of $3$ and $4$ is $12$. Multiply $\frac{x}{3}$ times $\frac{4}{4}$. Multiply $\frac{x+1}{4}$ times $\frac{3}{3}$.
$$\frac{4x}{12}-\frac{3\left(x+1\right)}{12}$$
Since $\frac{4x}{12}$ and $\frac{3\left(x+1\right)}{12}$ 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 $3$ and $4$ is $12$. Multiply $\frac{x}{3}$ times $\frac{4}{4}$. Multiply $\frac{x+1}{4}$ times $\frac{3}{3}$.
$$\frac{4x}{12}-\frac{3\left(x+1\right)}{12}$$
Since $\frac{4x}{12}$ and $\frac{3\left(x+1\right)}{12}$ have the same denominator, subtract them by subtracting their numerators.
