Question

доказать тождество (c^2-c-2)(c^2+c-2)=c^4-5c^2+4

Answer 1

c^4+c^3-2c^2-c^3-c^2+2c-2c^2-2c+4=c^4-5c^2+4
c^4-5c^2+4=c^4-5c^2 +4