36 = () + () 39 = () + () 91 = () + () prime

36 = () + () 39 = () + () 91 = () + () prime

36=（5）+（31） 39=（2）+（37） 91=（2）+（89）

91 = [] * [] prime

Decomposition quality factor:
91 = 7 × 13, 7 and 13 are prime numbers

Fill the 9 numbers 1,2,3,4,5,6,7,8,9 in brackets to make the equation hold
()()()=1/2*()()()=1/3*()()()

(2) (7) (3) = 1 × (5) (4) (6) = 1 × (8) (1) (9)

Matrix multiplication formula

In short, if C = AB, the number of row a and column B in C is row a of a multiplied by column B of B
For example, a = | A1 A2 | B = | B1 B2|
|a3 a4| B=|b3 b4|
Then C = | A1 * B1 + A2 * B3 A1 * B2 + A2 * B4|
|a3*b1+a4*b3 a3*b2+a4*b4|
So if a matrix of X1 rows and X2 columns is multiplied by a matrix of Y1 rows and Y2 columns, the result will be a matrix of X1 rows and Y2 columns
Is that straightforward enough

6,18,21,8,11,33,2,6,9,5,8,24,7,21, please give the last number!

6,18,21,18/6+18=21
8,11,33 (11-8)*11=33
2,6,9 6/2+6=9
5,8,24 (8-5)*8=24
7,21,24 21/7+21=24
The last number is 24

Please prove that the 1987 square of 2 + the 325 square of 3 × 5 can be divided by 17

2 + 3 × 5
= 2^3×(17 - 1)^496 + 3×5×(17 + 8)^662
= 8×(17 - 1)^496 + 15×(17 + 8)^662
According to the binomial expansion theorem, after the expansion of the above formula, the terms without factor 17 are only:
8 × (- 1) ^ 496 + 15 × 8 ^ 662, namely 8 + 15 × 2 ^ 1986
Because: 2 ^ 4 = 16 divided by 17-1, obviously 2 ^ 8 divided by 17-1
1986 ÷ 8 = 248 …… Yu 2
So the remainder of 2 ^ 1986 divided by 17 is equivalent to the remainder of 2 ^ 2 divided by 17, which is 4
To sum up, the original formula is congruent with: 8 + 15 × 4 = 68
And 68 △ 17 = 4 More than 0
Therefore, it is proved that 1 987 of 2 + 1 325 of 3 × 5 can be divisible by 17

Use 3,4. - 6,10 to make the result equal to 24

a. B is a negative number, C is an integer, where a and C are opposite numbers, the simplified formula is: the absolute value of a in a + the absolute value of B in B + C

∵ a < 0 and a and C are opposite numbers
∴c＞0
The absolute value of a in a is negative, because a is negative, so the absolute value of a in a is equal to a
Similarly, the absolute value of B out of B is also B
So the final result is a + B + C
The answers upstairs are just nonsense

Xiao Ming read a story book. On the first day, he read 1 / 4 of the total pages. On the second day, he read the remaining 1 / 3 and left 63
What if there are 64 pages left

This book has: 63 ^ (1-1 / 3) ^ (1-1 / 4)
= 63÷2/3÷3/4
=126 pages
This book has: 64 ^ (1-1 / 3) ^ (1-1 / 4)
= 64÷2/3÷3/4
=128 pages

The lengths of the two sides of the triangle are 5 and 12. The length of the third side is the root of the equation x-square-18x + 65 = 0. The circumference of the triangle is the shape of the triangle

The solution of the equation is x = 13 or 5, but according to the sum of the two sides is greater than the third side, we can know that 5 does not conform to 5 + 5