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.  

  • 3

(c) 3x-1

  • 5

d) 3x + 1

  • 4
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