48,32,17,3,14, (), 43,59 sequence A.28 B.33 C.31 D.27

48,32,17,3,14, (), 43,59 sequence A.28 B.33 C.31 D.27

48,32,17,14.3(A),43,59
a,28 b,33 c 31 d 27
59-48=11
43-32=11
28-17=11

The number of terms of sequence, 7,9,11,13,... 2N-1?

Let 2N-1 = 7, then 7 = 2x4-1, so there are n-4 + 1 = n-3 terms

Urgent, arithmetic series 7,9,11,13 The number of terms of 2N-1 is

n-3

How to prove that the difference between the sum of odd digits and the sum of even digits of a number is a multiple of 11, and the number can be divided by 11

Let an-1 A2a1 is an n-bit integer. If n is an odd number, then y = 11 × anan-1an-2 A2A1＝AnAn-1An-2… A2A1＋ An An-1An-2… A2a1 -- so y even digits add = an + (An-2 + an-1) + +(a1 + A2) and Y odd number addition = (an

There is a strange three digit number, which is exactly divided by 7 after subtracting 7, exactly divided by 8 after subtracting 8, exactly divided by 9 after subtracting 9______ ．

Because this strange three digit is divided by 7, 8 and 9, so this three digit is the least common multiple of 7, 8 and 9, 7 × 8 × 9 = 504

Is the square of any odd number minus 1 necessarily the abend of 8?
Be clear and step by step

Yes
(2n+1)^2-1
=(2n + 1 + 1) (2n + 1-1) (square difference formula)
=(2n+2)2n
=2(n+1)2n
=4n(n+1)
Because N and N + 1 are two adjacent numbers, there must be a number that is a multiple of 2 (2k)
Then 4N (n + 1) = 8kN or 8K (n + 1)
therefore
The square of any odd number minus 1 must be the COUNTEE of 8

What kind of number is the square of an odd number minus 1

The result of subtracting one from the square of an odd number can be divided by 8, for example, 3 & # 178; - 1 = 85 & # 178; - 1 = 249 & # 178; - 1 = 80. The reason is that if the odd number is 2K + 1 (k is an integer) (2k + 1) & # 178; - 1 = 4K & # 178; + 4K + 1-1 = 4K (K + 1) K and K + 1, one of them must be an integer, so K (K + 1) can be divided by 2, so 4K

After learning the common factor and decomposing the factor, answer the question: what is the result of the square of an odd number minus one

Let this odd number be (2x + 1)
Its Square-1 is expressed as (2x + 1) (2x + 1) - 1
because
A square - b square = (a + b) * (a-b)
therefore
The above formula is (2x + 2) * 2x
If there is a factor of 2, the result must be even

Graduation gift to Chinese, mathematics, English, sports, music, art teachers, Chinese, mathematics, English class representatives, monitor, deskmate and alma mater
Brief
In line with their own characteristics

Is the representative of mathematics class, my class's mathematics performance is very bad, the teacher asked me to make a speech to improve my interest in learning mathematics, and how to learn mathematics
Who can tell me how to say it or from which aspects
What do you need to listen and do more questions in class

Search "the beauty of mathematics in Google blackboard". After reading, you will know how to make a speech