3(2x-3)(2x+3)-(x-4)^2
3 [(2x-3)(2x+3)] - [ (x-4)^2 ]
3 [ 4x^2 - 9 ] - [ (x - 4) (x - 4) ]
12x^2 - 27 - [ x^2 - 8x + 16 ]
12x^2 - 27 - x^2 + 8x - 16 combine like terms
11x^2 + 8x - 43