ANSWER
B and C
Step-by-step explanation
The given expression has a fractional exponent. In a fractional exponent, the numerator is what we usually write as a power and the denominator is what we write as a root,
![a^(m/n)=\sqrt[n]{a^m}](https://img.qammunity.org/2023/formulas/mathematics/college/1rwg39gpyj2ie0s0ywq6ivmt1lmxografc.png)
In this case, option B shows this same form,
![(y+3)^(4/9)=\sqrt[9]{(y+3)^4}](https://img.qammunity.org/2023/formulas/mathematics/college/q8p8lwrozzt4hnant20s6i0fwaef8qimuk.png)
The power and the root are exchangeable because we can separate them as "power of a power" which is the product of the exponents - and the order of the factors does not matter.
Hence, option C is also equivalent,
![(y+3)^(4/9)=\sqrt[9]{(y+3)^4}=(\sqrt[9]{(y+3)})^4](https://img.qammunity.org/2023/formulas/mathematics/college/lzkfnd5n9q5jvfspp0f7cviuqhb86tj8bc.png)