Answer
$x=7$
Work Step by Step
$\frac{x}{7}+\frac{x}{5}=\frac{12}{5}$
The common denominator of these three fractions is $35$, so multiply the entire equation by $35$.
$(35)(\frac{x}{7})+(35)(\frac{x}{5})=(35)(\frac{12}{5})$
Simplify
$5x+7x=84$
Combine like terms
$12x=84$
Divide by $12$
$x=7$