Answer:
It is Commutative
Step-by-step explanation:
An operation ∆ is said to be Commutative if a∆b=b∆a ∀ a,b ∈ ℝ.
Given the operation ∆ defined by:
a∆b=a X b

a∆b=
=3
Similarly, for the right hand side.

Therefore:
b∆a=
=3
These are the two ways of solving this problem and we have in fact shown that the operation is commutative as:
a∆b=b∆a=3
400 = 2×2×2×2×5×5.
400 = 2^4 × 5^2 .
Use subtraction the answer is 44
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Answer:
And rounded up we have that n=421
Step-by-step explanation:
We know that the sample proportion have the following distribution:

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by
and
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
We assume that a prior estimation for p would be
since we don't have any other info provided. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=421