1.(a-3)(a+3)-2a(4-a)=
2.(3x-1)^2-(3x-1)^2=
3.5a^2+5ab=
4.4ac^2-8ac+4a^2c=
5.9n-n^3=
6.50ab-25a^2-25b^2=

1) a²-9 -8a+2a² =3a² -8a -92) =0, (3x-1)²(1 -1)=03) =5a(a +b)4) =4ac(c -2 +a)5) n(9 -n²) =n(3 -n)(3 +n)6) -25(a² -2ab +b²)= -25(a -b)²