Evaluate:

$\dfrac{1}{-15} + \dfrac{5}{-12}$

$\dfrac{-1}{15} + \dfrac{-5}{12} \\[1em]$

LCM of 15 and 12 is 2 x 2 x 3 x 5 = 60

$\dfrac{-1 \times 4}{15 \times 4} + \dfrac{-5 \times 5}{12 \times 5} \\[1em] =\dfrac{-4}{60} + \dfrac{-25}{60} \\[1em] =\dfrac{-4 + (-25)}{60} \\[1em] =\dfrac{-29}{60}$

∴ $\dfrac{1}{-15} + \dfrac{5}{-12} = \dfrac{-29}{60}$