Answer with Step-by-step explanation:
We are given that n and m are two integers
We have to prove that if n-m is even , then 
is also even.
We know that sum of two odd numbers is even.Sum of an odd number and even number is odd.
Product of an odd number and even number is even.
Case 1.Suppose m and n are both even n=4 , m=2
Case 2.Suppose m odd and n odd
n=9,m=5
Hence, proved.
Cost of the article = $27.50
Amount of city sales tax = (27.50 x 6%) = $1.65
Amount of excise tax = (27.50 x 8%) = $2.20
From my knowledge, we pay city sales tax and federal excise tax when we buy something, so the total cost would be $31.35
Number of ways = 6!
Number of ways = 6 x 5 x 4 x 3 x 2 x 1
Number of ways = 720
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Answer: 720 ways
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