А) (x+y)^2 - (x-y)^2 b) (2m-n)^2-(m+2n)^2
c) (3n+2p)^2-(5p-2n)^2
d) 4*(3x-2y)^2-9*(4x+3y)^2
Нужно разложить на множители двумя

x^2+2xy+y^2-(x^2-2xy+y^2)=x^2+2xy+y^2-x^2+2xy-y^2=4xy

4m^2-4mn+n^2-(m^2+4mn+4n^2)=4m^2-4mn+n^2-m^2-4mn-4n^2=3m^2-8mn-3n^2

c.9n^2+12np+4p^2-(25p^2-20pn+4n^2)=.9n^2+12np+4p^2-25p^2+20pn-4n^2=5n^2+32np-21p^2

d.4(9x^2-12xy+4y^2)-9(16x^2+24xy+9y^2)=36x^2-48xy+16y^2-144x^2-216xy-81y^2=-108x^2-168xy-65y^2