## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$\frac{41}{35}$
The greatest common denominator of $5$ and $7$ is $5 \times 7 = 35$. Therefore, $$\frac{3}{5}+\frac{4}{7}=\frac{3(7)}{35}+\frac{4(5)}{35}=\frac{21}{35}+\frac{20}{35}=\frac{41}{35}$$