## Calculus with Applications (10th Edition)

$\frac{51}{35}$
In order to subtract fractions with different denominators it is necessary to give them a common denominator In this example the simplest common denominator would be 35 To give both fractions a base multiply each by 1 For $\frac{13}{7}$ multiply by $\frac{5}{5}$: $\frac{13}{7}*\frac{5}{5} = \frac{65}{35}$ For$\frac{2}{5}$ multiply by $\frac{7}{7}$: $\frac{2}{5}*\frac{7}{7} = \frac{14}{35}$ Now because you have given each fraction a common denominator you can subtract normally $\frac{65}{35}-\frac{14}{35}=\frac{51}{35}$