Question

(a+b+c) (a+b-c)-(a+b) ²​

Answer 1

Step-by-step explanation:

(a+b+c) (a+b-c)-(a+b) ²

= {(a+b)+c} {(a+b)-c} - (a+b)²

= {(a+b)²- c²} - (a+b)²

= (a+b)²- c²- (a+b)²

= -c²

Algebraic identities used:

a²-b² = (a+b) (a-b)