One of the factors of (9x2 -1)-(1+3x)2 is
(a)3+x (b)3-x (c)3x-1 (d)3x+1
(9x2 –1) – (1 + 3x)2
= (3x –1)(3x + 1) – (1 + 3x)2
= (3x + 1){(3x –1) – (1 + 3x)}
= (3x + 1)(3x –1 – 1 – 3x)
= (3x + 1)(–2)
Thus, one factor of (9x2 –1) – (1 + 3x)2 is (3x + 1).
The correct answer is d.