The operation procedure of the new operation symbol * is defined as a * b = 1 3a−1 4b, then (1) Find 5 * (- 5); (2) Solve the equation 2 * (2 * x) = 1 * X

The operation procedure of the new operation symbol * is defined as a * b = 1 3a−1 4b, then (1) Find 5 * (- 5); (2) Solve the equation 2 * (2 * x) = 1 * X

(1) 5 * (- 5) = 13 × 5-14 × (- 5) = 53 + 54 = 3512; (2)

It is specified that * is an operation symbol and a * b = 2Ab + B? Try to calculate 4 * [(- 2) * 3]

-2*3 = 2 * -2 *3 + 9 = -3
4 * -3 = 2 * 4 * -3 + 9 = -15

If the sign "*" indicates the following operation: a * b = a + B 2, then (1 * 2) * - 3) = -___ .

Original formula = 1 + 2
2*（-3）
=3
2*（-3）
=3
2-3
Two
=-3
4．

If the sign "*" indicates the following operation: a * b = a + B 2, then (1 * 2) * - 3) = -___ .

Original formula = 1 + 2
2*（-3）
=3
2*（-3）
=3
2-3
Two
=-3
4．

Fill in the operation symbol 1 2 3 = 1?

（1＋2）÷3＝1

In mathematics, there is an operation called factorial. For example, 3! = 1 × 2 × 3, = 1x2x3x4, = 1x2x3x4x5

36! = 36 * 35 *. * 1; 35! = 35 * 34 *. * 1, so the result is 36

Factorial of what = 0

No, 0! = 1

How to express 1 * 3 * 5 * 7 *... * 2N-1 by factorial is better to have a derivation process I can't deduce the answer from this step to factorial

1*2*3*4*5*...*2n-1=(2n-1)!(1)
2*4*6*8*...*2n=2*(1*2*3*4*...*n)=2*n!(2)
(1)/(2)=1*3*5*7*...*2n-1=(2n-1)!/2n!

11 * 19 + 21 * 29 + 31 * 39 + 41 * 49 + 51 * 59 + 61 * 69 + 71 * 79 + 81 * 89 + 91 * 99 = 33081 Is there a way to do it in one step? Exclude for example: 10 * 20 + 9 + 20 * 30 + 9.. 90 * 100 + 9

(10+1)*(20-1)+(20+1)(30-1)+...+(90+1)(100-1)
=(200+10-1)+(600+10-1)+(1200+10-1)+...+(9000+10-1)
=200+600+1200+2000+3000+4200+5600+7200+9000+81
=33081

81 Gongge sudoku-8-7-1-5-7-8 54-8-61-7-3-9-5-8-9-6-51-3-76 3-4-2-8-2-4-1

*-----------------------------------------------*
| 9 8 2| 7 4 1| 6 3 5|
| 6 7 1| 3 5 9| 2 4 8|
| 5 4 3| 8 2 6| 1 9 7|
|---------------+---------------+---------------|
| 4 2 8| 5 3 7| 9 6 1|
| 7 5 6| 9 1 2| 3 8 4|
| 1 3 9| 4 6 8| 7 5 2|
|---------------+---------------+---------------|
| 2 9 5| 1 8 3| 4 7 6|
| 3 1 4| 6 7 5| 8 2 9|
| 8 6 7| 2 9 4| 5 1 3|
*-----------------------------------------------*