Step-by-step explanation:

I think, he made a mistake because the exponents have different values but then if you'll look at his results, he just wrote the same thing. If you want, you could post the original problem, and I'll solve it for you :)
The weight of water in swimming pool is 13305600kg
Answer:
Step-by-step explanation:
x² = 40² + 9²
= 1600 + 81
x² = 1681
x = √1681
x= 41
It’s P.E.M.D.A.S
P= parenthesis ()
E= exponent
M= multiplication or Multiply
D= Division or divided
A= Addition
S= Subtraction
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