Question

Помогите с этими номерами, прошу

Answer 1

(a+b)^2-(a-b)^2=a^2+2ab+b^2-a^2+2ab-b^2=4ab

Answer 2

4) (c^2-b)^2-(c^2-1)(c^2+1)+2bc^2=c^4-2bc^2+b^2-(c^4-1)+2bc^2=c^4-2bc^2+b^2-c^4+1+2bc^2=b^2+1
5) (a+b)^2-(a-b)^2=a^2+2ab+b^2-a^2+2ab-b^2=4ab