Question

Evaluate by using suitable identities (a + b + c)^2 – ( a – b + c)^2

Answer 1

Answer:

4(ab+bc)

Step-by-step explanation:

as $x^{2} - y^{2} =(x+y)(x-y)$

so put x= a+b+c

and y= a-b+c

so

$(a+b+c)^{2} - (a-b+c)^{2} = (a+b+c +a-b+c)(a+b+c -a+b-c)\\\\ = (2a+2c)(2b)\\ =2*2(a+c)(b)\\ = 4(ab+bc)$