Math

[Guest]

Factor:
(-ab-bc)(cd-da)-1-b(2acd-2c²d).

[shyamjayakannan]

[tex](-ab-bc)(cd-da)-1-b\left(2acd-2c²d\right)=-bd(a+c)(c-a)-1-2bcd(a-c)=bd(a-c)(a+c-2c)-1[/tex]
[tex]=\boxed{bd(a-c)^2-1}[/tex]