Let's solve this equation step by step:

(3x+1)^2 - (3x-1)^2 = 11x + 1.2

Expanding both terms:

(9x^2 + 6x + 1) - (9x^2 - 6x + 1) = 11x + 1.2

Simplify the equation:

9x^2 + 6x + 1 - 9x^2 + 6x - 1 = 11x + 1.2

Combine like terms:

12x = 11x + 1.2

Subtract 11x from both sides:

12x - 11x = 1.2

Simplify:

x = 1.2

Therefore, the solution to the equation is x = 1.2.