Answer:
x⁷y⁷
Explanation:
An exponent signifies the base is a repeated factor in the product. The exponent is the number of times it is a factor.
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The term (xy)^7 means (xy) is a factor 7 times:
= (xy)·(xy)·(xy)·(xy)·(xy)·(xy)·(xy)
The commutative and associative properties of multiplication let us rearrange this to ...
= (x·x·x·x·x·x·x)·(y·y·y·y·y·y·y)
= (x^7)(y^7)
The expression can be simplified to ...

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The rule of exponents is ...
(ab)^c = (a^c)(b^c)