Answer
$84=2 \cdot 2 \cdot 3 \cdot 7$
Work Step by Step
The number is even, so factor out 2 to obtain:
$84= 2 \cdot 42 $
42 is even, so factor out 2 again to obtain:
$84 = 2 \cdot 2 \cdot 21$
21 is divisible by 3 so factor out 3 to obtain:
$84=2 \cdot 2 \cdot 3 \cdot 7$