# one factoring question

• January 13th 2008, 10:10 AM
checkmarks
one factoring question

(4x+1)^2 - (16x^2 + 4x)

i treated it as a difference of squares
so i did:
(4x+1 + 16x^2+4x)(4x+1 - 16x^2 - 4x)
which i further simplified to:
(16x^2 +8x+1)(-16x^2 +1)

and im pretty sure this isnt right.
• January 13th 2008, 11:33 AM
Soroban
Hello, checkmarks!

Quote:

Factor: . $(4x+1)^2 - (16x^2 + 4x)$

i treated it as a difference of squares . . . . ${\color{blue}(16x^2 + 4x)}$ is not a square

Factor the second term: . $(4x+1)^2 - 4x(4x + 1)$

Take out the common factor: . $(4x+1)\bigg[(4x+1) - 4x\bigg]$

And we have: . $(4x + 1)[4x + 1 - 4x) \;\;=\;\;(4x+1)(1) \;\;=\;\;\boxed{4x + 1}$