If you meant to say (3x+2)^2, then the answer is 9x^2+12x+4
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Step-by-step explanation:
You would use the FOIL rule to get
(3x+2)^2
(3x+2)(3x+2)
(3x)*(3x) + (3x)(2) + 2(3x) + 2*2
9x^2 + 6x + 6x + 4
9x^2 + 12x + 4