What is the simple operation of 27 × 24 × 25?

What is the simple operation of 27 × 24 × 25?

27×24×25
= 27×6×4×25
= (27×6)×(4×25)
= 162×100
= 16200

Finding the general formula of - 1 / 3,1 / 8, - 1 / 15,1 / 24

(-1)^n/n(n+2)

There is a number, smaller than 20, which is even, with a divisor of 3 and a multiple of 4. This number is ()
A. 6B. 8C. 18D. 12

3 × 4 = 12, therefore, smaller than 20, is an even number, has a divisor 3 and a multiple of 4, this number is 12; so choose D

A+B+C+D=22 A+B+C-D=12 A+B-C+D=8 A-B+C+D=18
A=( ) B=( ) C=( ) D=( )

A=(4)B=(8/7)C=(8/5)D

Calculation (5a-4b) (- 5a-4b)

Original formula = (- 4B + 5a) (- 4b-5a)
=（-4b）²-（5a ）²
=16b²-25a²

Simple calculation of the square of (5a-4b) - 2 (5a-4b) (- 5a-4b)

The original solution = (25a & # 178; - 40ab + 16b & # 178;) + 2 (5a-4b) (5a + 4b) = (25a & # 178; - 40ab + 16b & # 178;) + 2 (25a & # 178; - 16b & # 178;) = (25a & # 178; + 50A & # 178;) - 40ab + (16b & # 178; - 32B & # 178;) = 75A & # 178; - 4ab-16b & # 178;);

regulations A@B=5A-4B , if x@（ 5@2 ）=12, then the value of X is (). (@ stands for operation symbol)

5@2=5 ×5－4×2=17
x@( 5@2 ) =x@17
5x－4×17=12
5x=12+68
5x=80
x=16