Question

因式分解 a^2-b^2-4a+2b+3

Answer 1

a^2-b^2-4a+2b+3

=a^2-4a-b^2+2b+3

=a^2-4a+4-b^2+2b-1

=(a^2-4a+4)-(b^2-2b+1)

=(a-2)^2-(b-1)^2

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

=(a+b-3)(a-b-1)