Verified answer

An exponent outside parentheses or brackets goes with everything inside. It raises numbers to that exponent power, and gets multiplied by other exponents. You'd do that first here, giving you

2^-2 a^-6 b^4 a^2 c^-4

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(-4)^-1 a^-1 b^1 c^-4

Next, evaluate the numbers in front.

Negative exponents mean reciprocals. 2^-2 = 1/4 and (-4)^-1 = - 1/4.

Those will then cancel leaving just -1.

The exponents of variables that are multiplied get added, and divided variables' exponents get subtracted. So first combine the a^-6 • a^2 on top to become a^-4...

-1 a^-4 b^4 c^-4

----------------------- then subtract the exponents of each variable

a^-1 b^1 c^-4

-1 a ^(-4 - -1) b^(4 - 1) c^(-4 - -4)

= -a^-3 b^3 c^0

Anything to the 0 power = 1 and a^-3 is 1/a^3 so the final answer is -b^3 over a^3