Respuesta :
If you are looking for the expanded version, this is it. It is also possible to group either an a from (a^2 + 2b) or a b from (2ab + b^2). Hope this helps!

Answer:
[tex](a+b-c)(a+b+c)=a^2+2ab+b^2-c^2[/tex].
Step-by-step explanation:
We want to expand: [tex](a+b-c)(a+b+c)[/tex].
We use the distributive property to obtain:
[tex](a+b-c)(a+b+c)=a(a+b+c)+b(a+b+c)-c(a+b+c)[/tex].
We now expand to get:
[tex](a+b-c)(a+b+c)=a^2+ab+ac+ab+b^2+bc-ac-bc-c^2[/tex].
This finally simplifies to
[tex](a+b-c)(a+b+c)=a^2+2ab+b^2-c^2[/tex].