Can anyone solve it? My answer is -2 which is wrong.

But if we multiply 2x2x2x2 the answer is 16 in this way we can cancel exponent 4?

The answer on that website is the following

That’s another way of solving, but i found the same answer as your website,

2 * ⁴square root -1 is the same as 2 * ²square root -1

Be careful with the notation of the answer, 4 is the index of the root, not the exponent of 2