Answer
$-\dfrac{41}{35}$
Work Step by Step
Make the fractions similar using their LCD, which is $35$, to obtain:
$=-\dfrac{21}{35} - \dfrac{20}{35}$
RECALL:
$a-b = a+(-b)$.
Thus,
$-\frac{21}{35} - \frac{20}{35}=-\frac{21}{35} +\left(-\frac{20}{35}\right)=-\frac{41}{35}$
