(3x+4y)в квадрате - (4y-3x)в квадрате =
=((4y+3х)-(4y-3x))((4y+3х)+(4y-3x))=
=(4y+3х-4y+3x)(4y+3х+4y-3x)=6x*8y=48ху
(3x+4y)в квадрате - (4y-3x)в квадрате =
=((4y+3х)-(4y-3x))((4y+3х)+(4y-3x))=
=(4y+3х-4y+3x)(4y+3х+4y-3x)=6x*8y=48ху