Which expressions represent a perfect square monomial and its square root? Check all that apply.

A perfect square monomial has a square root whose square equals the given monomial. Since 11² = 121, choice A works; since (2x)² = 4x², choice B works; and since (7x²)² = 49x⁴, choice E works. Choice C is not a monomial, and (3x − 1)² is not 9x² − 1. Choice D does not work because (5x)² = 25x², not 25x.

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