Find the value of x if

Answer:
C. 4
Step-by-step explanation:
We have the equation [tex]\sqrt[x]{81} =3[/tex] and are asked to find the value of x.
To find x, we need to find how many times 3 can go into 81 but as an exponent, instead of saying 3 * x it would be [tex]3^x[/tex].
So find the value of each exponent by replacing it with each answer choice :
[tex]3^8 = 6561[/tex]
[tex]3^{27} = 7.6255975e+12[/tex]
[tex]3^4 = 81[/tex]
[tex]3^2 = 9[/tex]
Since to the power of 4 equals the cube root in the original equation, therefore B. is the answer.