Answer: D. (3x + 1)(3x+1)
Step-by-step explanation:
9x² + 6x + 1
find two factor of 9 such that its product gives 9 and its sum gives 6 (3 and 3, 3×3 = 9 , also 3+ 3=6)
we are going to replace 6x by 3x + 3x
9x² + 6x + 1
9x² + 3x +3x + 1
3x(3x + 1) + 1(3x+ 1)
(3x + 1)(3x+1)
