(2+c)(2-c)+(c-3)^2-3(4-2c)

Question

(2+c)(2-c)+(c-3)^2-3(4-2c)

Answer 1

(2+c)(2-c)+(c-3)²-3(4-2c)=(4-c²)+(c²-6c+9)-(12-6c)=
=4-c²+c²-6c+9-12+6c=1

Formuli: (a+b)(a-b)=a²-b², (a-b)²=a²-2ab+b²