(11^-4)^-6 = 11 , How is that?

If you're supposed to show that (11^-4)^-6 = 11; it doesn't.

If you're supposed to find the exponent on 11 to make it true:  since you have an exponent to an exponent, multiply the exponents together:  -4 x -6  =  24.       11^24 is the simplified expression.

$${\left({{\mathtt{11}}}^{-{\mathtt{4}}}\right)}^{-{\mathtt{6}}} = {\mathtt{9\,849\,732\,675\,807\,611\,094\,711\,841}}$$