(3x+2)(3x-2)-5x(x-1)-(2x-1)^2=9x^2-4-5x^2+5x-4x^2+4x-1=9x-5
直接展开即可：原式子= 9x^2 -4 -5x^2 + 5x -4x^2 + 4x -1=9x-5
