Выполните действия (2m+c)(2m-c)-(3c-m)^2+2(5c+2m)(c-m)

Question

Выполните действия
(2m+c)(2m-c)-(3c-m)^2+2(5c+2m)(c-m)

Answer 1

(2m+c)(2m-c)-(3c-m)²+2(5c+2m)(c-m)=(4m²-c²)-(9c²-6cm+m²)+2(5c²+2mc-5cm-2m²)=
=4m²-c²-9c²+6cm-m²+10c²-6cm-4m²=-m²