Answer
$5x^{2}y^{3}+2xy-y^{2}$
Work Step by Step
$(3x^{2}y^{3}-xy+4y^{2})-(-2x^{2}y^{3}-3xy+5y^{2})=$
... distribute the -1 over the second parentheses
$=3x^{2}y^{3}-xy+4y^{2}+2x^{2}y^{3}+3xy-5y^{2}$
... gather like terms
$=3x^{2}y^{3}+2x^{2}y^{3}-xy+3xy+4y^{2}-5y^{2}$
... add like terms
=$5x^{2}y^{3}+2xy-y^{2}$