Answer:
[tex]\huge\boxed{\sf 9x^2+12x+4 \ units^2}[/tex]
Step-by-step explanation:
Given that,
Length of cube = l = 3x + 2 units
[tex]= l \times l\\\\= (3x+2)(3x+2)\\\\= 3x(3x+2)+2(3x+2)\\\\= 9x^2+6x+6x+4\\\\= 9x^2+12x+4 \ units^2\\\\\rule[225]{225}{2}[/tex]
