помогите 2) и 4) и 6) и 8)

2) (a-2)^2=(a-2)*(a-2)=a^2-2a+2a-4=a^2-4a-4
4) (y+3)^2=(y+3)*(y+3)=y^2+3y+3y+9=y^2+6y+9
6)(c+d)^2=(c+d)*(c+d)=c^2+cd+cd+d^2=c^2+2cd+d^2
8) (k+m)^2=(k+m)*(k+m)=k^2+km+km+m^2=k^2+2km+d^2