## College Algebra (10th Edition)

$\dfrac{5}{42}$
Find the LCM (lease common multiple) of the denominators: $14 = 7(2) \\21=7(3)$ The LCM is $7(2)(3) = 42$ Thus, the LCD is also $42$ Make the fractions similar using their LCD to obtain: $=\dfrac{3(3)}{14(3)} - \dfrac{2(2)}{21(2)} \\=\dfrac{9}{42}-\dfrac{4}{42} \\=\dfrac{9-4}{42} \\=\dfrac{5}{42}$