So the question is (5x^7)^2. (Assuming that the 2 means powered of 2.
This would equal 5^2 * w^(7*2)
Remember, we are multiplying 7 and 2, because that's a rule that this exponent follows.
This would give us 25w^14.
So the answer is 25w^14.
Hope this helps.
If you have any questions, please put them in the comments below.