Determine whether the expressions are equivalent or not.

? Equivalent Not Equivalent  1. $\sqrt{x^4 + 81}$ and $(x^4 + 81)^{0.5}$

? Equivalent Not Equivalent  2. $\sqrt{x^4 + 81}$ and $x + 3$

? Equivalent Not Equivalent  3. $\sqrt{x^4 + 81}$ and $x^2 + 9$

? Equivalent Not Equivalent  4. $\sqrt{x^4 + 81}$ and $(x+3)^2$

? Equivalent Not Equivalent  5. $\sqrt{x^4 + 81}$ and $(x^4 + 81)^{1/2}$