The LCD = 6x^2y^3 ( because LCD of 3 and 6 = 6, LCD of x^2 and x = x^2 and LCD of y and y^3 = y^3)
now divide 3x^2y into the LCD then multiply this by 5 to get the first term in the numerator and do similar process to get second term, so we get:-
5(2y^2) - 4(x)
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6x^2y^3
= 2( 5y^2 - 2x)
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6x^2y^3
= 5y^2 - 2x
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3x^2y^3