Question

expand (a+b+c)(a+b-c) using (x+y)(x-y) property​

Answer 1

Answer:

take {(a+b)+c}{(a+b)-c} as (x+y)(x-y)

= {(a+b)^2-(c)^2}

= a^2+b^2+2ab-c^2

Answer 2

Answer:

a²+b²-2ab-c²

Step-by-step explanation:

let a+b=d

therefore,

(a+b+c)(a+b-c) =(d+c)(d-c)

by using (x+y)(x-y) property we get

d²-c²

on resubstituting d=a+b,

(a+b)²-c²

=(a²+2ab+b²)-c²

=a²+b²-2ab-c²