Answer
$x=7$
Work Step by Step
$\frac{x}{7}+\frac{x}{5}=\frac{12}{5}$
$\frac{x}{7} \times \frac{5}{5} + \frac{x}{5} \times \frac{7}{7} = \frac{12}{5} \times \frac{7}{7}$
$\frac{5x}{35}+\frac{7x}{35}=\frac{84}{35}$
$\frac{12x}{35}=\frac{84}{35}$
$12x=84$
$x=7$