8+(a-2b+1)(a+1)-(a-2b)(a+2b)

Question

8+(a-2b+1)(a+1)-(a-2b)(a+2b)

Answer 1

8+(a-2b+1)(a+1)-(a-2b)(a+2b)=8+(a^2-2ab+a+a-2b+1)-(a^2-4b^2)=8+a^2-2ab+2a-2b+1-a^2+4b^2=9+4b^2-2ab+2a-2b

Answer 2

8+(a-2b+1)(a+1)-(a-2b)(a+2b)=8+a^2+2a-2ba-2b+1-(a-2b)*(a+2b)=9+a^2+2a-2ba-2b-(a-2b)*(a+2b)=9+a^2+2a-2ba-2b-(a^2-4b^2)=9+a^2+2a-2ba-2b-a^2+4b^2=4b^2-2ba+2a-2b+9