In factorization, we write the middle term of the quadratic equation either as a sum of two numbers or difference of two numbers such that the equation can be factorized.

⇒ abx² – acx + b²x – bc = 0

⇒ ax(bx – c) + b(bx – c) = 0

⇒ (ax + b)(bx – c) = 0

⇒ x = -b/a, c/b