(-2xy+y)²
=4x^2y^2-4xy^2+y^2
[(a-2b)(a+2b)-(a+2b)²]÷(-2b)
=(a^2-4b^2-a^2-4ab-4b^2)÷(-2b)
=(-8b^2-4ab)÷(-2b)
=4b+2a
[(xy-2)²-2(x²y²+2)]÷(xy)
=(x^2y^2-4xy+4-2x^2y^2-4)÷(xy)
=(-4xy-x^2y^2)÷(xy)
=-4-xy
(-2xy+y)²
=4x^2y^2-4xy^2+y^2
[(a-2b)(a+2b)-(a+2b)²]÷(-2b)
=(a^2-4b^2-a^2-4ab-4b^2)÷(-2b)
=(-8b^2-4ab)÷(-2b)
=4b+2a
[(xy-2)²-2(x²y²+2)]÷(xy)
=(x^2y^2-4xy+4-2x^2y^2-4)÷(xy)
=(-4xy-x^2y^2)÷(xy)
=-4-xy