(5c-6d)(5c+6d)-25c^2

Надо сократить?

(5с-6d)(5c-6d)-25c^2=

=(5c)^2 - (6d)^2 - (5c)^2= -(6d)^2=- 36d^2

(5c-6d)(5c+6d)-25c^2=25c^2-36d^2-25c^2=-36d^2