Question

simplify (a+b+c)^2-(a-b-c)^2

Answer 1

{(a+b+c)+(a-b-c)}×{(a+b+c)-(a-b-c)} =(a+b+c+a-b-c)×(a+b+c-a+b+c) =2a×(2b+2c) =4a (b+c)