Example 1 M? +4m- 12 factorization?
Analysis: The quadratic term in this question can only be divided into 1× 1, and the constant term-12 can be divided into-1× 12, -2×6, -3×4, -4×3 and-6× 4.
The quadratic term on the left and the constant term on the right are multiplied obliquely, and the sum of them is equal to the linear term.
1╳6
1╳-2
( 1×6)+( 1×-2)=4