Question

(3x+4y)^2-(4y-3x)^2=48xy докозать тождества

Answer 1

(3х+4у)^2-(4у-3х)^2=48ху
(3х+4у)^2-(4у-3х)^2=9х^2+24ху+16у^2-(16у^2-24ху+9х^2)=9х^2+24ху+16у^2-16у^2+24ху-9х^2=24ху+24ху=48ху
48ху=48ху

Answer 2

$(3x+4y)^2 - (4y-3x)^2 = 48xy$
$9x^2 +24xy + 16y^2 - (16y^2 - 24xy + 9x^2) = 48xy$
$9x^2 + 24xy + 16y^2 - 16y^2 + 24xy - 9x^2 = 48xy$
$48xy = 48xy$
Тождество доказано
Надеюсь, помог