Final answer:
None of the options provided (x+y⁵, x+y⁶, 3x+2y³, 3x+2y⁵, 3x+2y⁶) are equivalent to the expression x²+y³ since the coefficients and exponents in each option are different, resulting in expressions that represent different values.
Step-by-step explanation:
The expression x²+y³ is not equivalent to any of the options provided. When considering expressions to be equivalent, they must represent the same mathematical expression or value for all values of the variables involved. Looking at the options given:
None of these expressions are equivalent to x²+y³ because each term in the provided options is altered either by different numerical coefficients or by different exponents. Exponents in particular define the power to which a number is raised to and thus drastically change the value it represents.