If a is an even integer and b is an odd integer then prove a − b is an odd integer
Let a be our even integer
Let b be our odd integer
We can express a = 2x (Standard form for even numbers) for some integer x
We can express b = 2y + 1 (Standard form for odd numbers) for some integer y
a - b =...
Let us take an integer x which is both even and odd.
As an even integer, we write x in the form 2m for some integer m
As an odd integer, we write x in the form 2n + 1 for some integer n
Since both the even and odd integers are the same number, we set them equal to each other
2m = 2n + 1...
Take two arbitrary integers, x and y
We can express the odd integer x as 2a + 1 for some integer a
We can express the odd integer y as 2b + 1 for some integer b
x + y = 2a + 1 + 2b + 1
x + y = 2a + 2b + 2
Factor out a 2:
x + y = 2(a + b + 1)
Since 2 times any integer even or odd is always...
n^2+n = odd
Factor n^2+n:
n(n + 1)
We have one of two scenarios:
If n is odd, then n + 1 is even. The product of an odd and even number is an even number
If n is even, then n + 1 is odd. The product of an even and odd number is an even number
n^2-n = even
Factor n^2-n:
n(n - 1)
We have one of two scenarios:
If n is odd, then n - 1 is even. The product of an odd and even number is an even number
If n is even, then n - 1 is odd. The product of an even and odd number is an even number
If n represents an odd integer what represents the previous smaller odd integer
Each odd integer is 2 away from the last one, so the previous smaller odd integer is found by subtracting 2 from n:
n - 2
2 consecutive odd integers such that their product is 15 more than 3 times their sum.
Let the first integer be n. The next odd, consecutive integer is n + 2.
We are given the product is 15 more than 3 times their sum:
n(n + 2) = 3(n + n + 2) + 15
Simplify each side:
n^2 + 2n = 6n + 6 + 15
n^2...
The sum of 5 odd consecutive numbers is 145.
Let the first odd number be n. We have the other 4 odd numbers denoted as:
n + 2
n + 4
n + 6
n + 8
Add them all together
n + (n + 2) + (n + 4) + (n + 6) + (n + 8)
The sum of the 5 odd consecutive numbers equals 145
n + (n + 2) + (n + 4) + (n + 6)...
Roberto has taken 17 photos photos are placed on each odd number page and the newspaper has 10 pages total. The pages with photographs will have 3 or 4 photos each. How many pages has 3 photos and how many pages have 4 photos?
Odd pages are 1, 3, 5, 7, 9
17/5 = 3 with 2 remaining.
So all 5...