1, the method of cross multiplication: the left multiplication of the cross is equal to the quadratic term coefficient, the right multiplication is equal to the constant term, and the cross multiplication is equal to the linear term coefficient.

1), using cross multiplication to solve some simple and common problems. Example 1 put m? Factorial analysis of +4m- 12: The constant term-12 in this question can be divided into-1× 12, -2×6, -3×4, -4×3, -6×2 and-/kloc. +4m- 12=(m-2)(m+6) Example 2 5? +6x-8 factorization factor