The answer you've been given is wrong. The only way for the expression to simplify that way would be for the original expression to change the power on the first of the "y" terms in the denominator:
The answer you've been given is wrong. The only way for the expression to simplify that way would be for the original expression to change the power on the first of the "y" terms in the denominator:
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... but is it still possible to simplify further? like maybe