There are two solutions. The other tutor did not get both solutions.
I'll go into a little more detail.



Raise both sides of the equation to the reciprocal of 
power, which is the  power:



Remove the parentheses on the left by multiplying the exponents 
which just gives the exponent 1.

On the right we use the rule: 

But since the root we are taking is even, the fourth root,
there are two fourth roots, positive and negative, so we must
precede it by ±:












So there are two solutions, 

 and 

Edwin

Another way to get both solutions is this:



Raise both sides to the 5th power



Multiply exponents



Use the principle of even roots (fourth root):









That way you get both solutions.

Edwin