(a+b)？ Expansion formula: a? +3a？ b+3ab？ +b？ .

(a-b)? Expansion formula: a? -3a？ b+3ab？ -B? .

All cubic formulas include all cubic sum formula and all cubic difference formula. The complete cubic sum (or difference) formula means that the cube of the sum (or difference) of two numbers is equal to three times the sum (or difference) of the cubic sum (or difference) of these two numbers and the square of each number multiplied by the sum (or difference) of another number.

Related content explanation:

Cubic difference formula and cubic sum formula are collectively called cubic formula, and their basic descriptions are as follows:

1, the cubic sum formula, that is, the cubic sum of two numbers is equal to the product of the difference between the sum of these two numbers and the sum of their squares and the product of these two numbers. It can also be said that the cubic sum of two numbers is equal to the product of the product of these two numbers and the incomplete square of the difference between these two numbers.

2. Cubic difference formula is also one of the commonly used formulas in mathematics, which has some contact in high school mathematics and occupies a very important position in mathematical research, even in advanced mathematics and calculus. Cubic difference formula and cubic sum formula * * * are called complete cubic formula.