Question

12x² - 7x +1 here the answer is (3x-1) (4x+1). From where did 4x come

Answer 1

when we factorise the given equation as follow
${12x }^{2} - 7x + 1 \\ {12x}^{2} - 4x - 3x + 1 \\ 4x(3x - 1)1(3x - 1) \\ (4x + 1)(3x - 1)$

by 3rd step 4x come