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.

⇒ 3(7x + 1)² – 4(5x – 3)² = 11(5x – 3)(7x + 1)

⇒ 3(49x² + 1 + 14x) – 4(25x² + 9 – 30x) = 11(35x² – 3 – 16x)

⇒ 338x² – 338x = 0

⇒ x(x – 1) = 0

⇒ x = 0, 1