is this correct...

Question

(3x^2+4x-3)^2-(3x^2-x+2)^2

then is it this

(9x^4+24x^3-2x^2-24x+9)-(9x^4-6x^3+13x^2-4x+4)

or this

9x^4+24x^3-2x^2-24x+9-9x^4-6x^3+13x^2-4x+4

should it have brakets or not that's my only problem

thanks