Factorization is to convert a long series of formulas connected by addition and subtraction signs into the product of several polynomials.

Give a simple example, such as putting X? 0? 5-x becomes x(x- 1).

Cross multiplication is used for quadratic trinomials (such as 2x? 0? 5+7x+6)。

Take 2x? 0? For example, 5-7x+6, this formula seems to be factorizable. But we divide the quadratic coefficient (that is, 2) into 2= 1×2, divide the constant term into 6=2×3, and then write these four numbers into two lines:

1 2

2 3

Cross multiplication: 1×3=3, 2×2=4, and then add and subtract to make the sum equal to the first-order coefficient, that is, 3+4=7.

If this situation is not satisfied, we will keep changing numbers, such as dividing 6 by 6=(-2)×(-3), and then until the above situation is satisfied.

So 2x? 0? 5+7x+6 can be decomposed into a formula with the above numbers as coefficients: (1x+2)×(2x+3).

That's all for now.