1)(x-12)(x+12)=xˇ2-144
2)(3a+2b)(2b-3a)=(2b+3a)(2b-3a)=4bˇ2-9aˇ2
3)(-4nˇ3+n)(n+4nˇ3)=nˇ2-16nˇ6=nˇ2(1-16nˇ4)=nˇ2(1-(4nˇ2))=
=nˇ2(1+2n)(1-2n)
4)(14+x)(14-x)=196-xˇ2
5)(5a+3b)(3b-5a)=9bˇ2-25aˇ2
6)(2nˇ2+n)(-2nˇ2+n)=(n+2nˇ2)(n-2nˇ2)=nˇ2-4nˇ4=
=nˇ2(1-4nˇ2)=nˇ2(1+2n)(1-2n)