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What is cubic difference formula (a-b)3?
Cubic formula (a-b)3 is a complete cubic difference formula. The complete cubic difference formula is a mathematical formula, namely (a-b)? =a? -3a? b+3ab? -B? Cubic sum formula. (a-b)? =a? -3a? b+3ab? -B? .

Note: In (a-b)? =a? -3a? b+3ab? -B? In, its number is "+,-". +,-"after the first letter is arranged, and it is a homogeneous formula (3 times for each term), and its coefficients are 1, -3, +3,-1, and the result is a quartic formula.

Decomposition process of cubic formula;

The difference between two numbers multiplied by the sum of their squares and the sum of their products is equal to the cube of the difference between two numbers.

(a-b)? =a? -3a? b+3ab? -B?

So a? -B? =(a-b)? -[-3(a? )b+3ab? ]=(a-b)(a-b)? +3ab(a-b)

=(a-b)(a? -2ab+b? +3ab)=(a-b)(a? +ab+b? :

( 1)a? +b? =(a+b)(a? -ab+b? )。

(2)a n+b n =(a+b)[a(n- 1)-a(n-2)×b+...+(- 1) (r- 1 )× a(。