Question 317821
{{{(6x^7/2x^2)^-4}}}
There are many ways to simplify this. I think it would be easier to simplify the inside fraction first, as then you would be working with smaller numbers.

Remember, you simplify numbers separate from pronumerals. 
= {{{(3x^7/x^2)^-4)}}}
Note that when you cancel out the {{{x^2}}}, the answer is 1, not 0
= {{{(3x^5/1)^-4}}}
A negative indice means you find the reciprocal of the fraction. In other words, to remove the negative from the indice, flip the fraction.
= {{{(1/3x^5)^4}}}
= {{{1/81x^20}}}