х(х+3)-(х+2)^2+(х-4)(х+4)=
=х^2+3х-(х^2+4х+4)+(х^2+4х-4х-16)=
=х^2+3х-х^2-4х-4+х^2+4х-4х-16=
=х^2-х^2+х^2+3х-4х+4х-4х-4-16=
=х^2-х-20
х(х+3)-(х+2)^2+(х-4)(х+4)=
=х^2+3х-(х^2+4х+4)+(х^2+4х-4х-16)=
=х^2+3х-х^2-4х-4+х^2+4х-4х-16=
=х^2-х^2+х^2+3х-4х+4х-4х-4-16=
=х^2-х-20