42a^5-6a^2/6a

= 42a^5 - 6a^2 / 6a

To simplify this expression, we first divide the terms individually:

= 42a^5 / 6a - 6a^2 / 6a

Next, we simplify by dividing the coefficients and subtracting the exponents:

= 7a^(5-1) - a^(2-1)

= 7a^4 - a

Therefore, the simplified expression is 7a^4 - a.