Answer:

Step-by-step explanation:
The last one is also the answer
Using the rational exponet rule,
![\sqrt[n]{ {x}^{m} } = x {}^{ \frac{m}{n} }](https://tex.z-dn.net/?f=%20%5Csqrt%5Bn%5D%7B%20%7Bx%7D%5E%7Bm%7D%20%7D%20%20%3D%20x%20%7B%7D%5E%7B%20%5Cfrac%7Bm%7D%7Bn%7D%20%7D%20)
Using this number,

40 is the base so it will stay same. Remember this is a square root sign so our nth root is 2 so our denominator if the rational exponet is 2.

so our numerator is 1 so

Answer:
Here the answer LOL
Step-by-step explanation:
So first write out the expression:

take two 10's from the top to cancel with the two 10's on the bottom.
3.9/1.3 is 3.
The answer is 3*10^3
3x9=27
21/3 = 7
so
7+27x9+5
27x9=243
243+7+5
answer is 255