Question

分解因式:①a的3次方-a²b-2ab+b²-1,②x²-4y²+x-2y

Answer 1

=a^3-2ab-b^2-1=a^3-2ab-b^2-1+a^2-a^2=(a-b)^2-1-a^2-a^2b+a^3=(a-b-1)(a-b+1)+a^2(a-b-1)=(a-b+1+a^2)(a-b-1)=x^2+x+1/4-4y^2-2y-1/4=(x+1/2)^2-(2y+1/2)^2=(x+1/2-2y-1/2)(x+1/2+2y+1/2)=(x-2y)(x+2y+1)