To convert the fraction 6/7 to a fraction with a denominator of 42, we need to determine what number we have to multiply the denominator (7) by to get 42.
Since 7 x 6 = 42, we multiply both the numerator and the denominator of 6/7 by 6. This gives us:
6 x 6 = 36
So, the fraction becomes:
6/7 = 36/42
Therefore, 6/7 written as a fraction with a denominator of 42 is 36/42.