Question

please ans fast. ................

Answer 1

$formulae \: used \\ a ^{2} - b^{2} = (a - b)(a + b)$
a=(x+y+z)
b=(x-y+z)
so,
$(x + y + z + x - y + z)(x + y + z - (x - y + z) \\ (2x + 2z)(2y) \\ 4xy + 4yz$

Answer 2

(x+y+z)pwr2 -(x-y+z)pwr2
=
$x2 - b2$
(x+y+z+x-y+z)(x+y+z-x+y-z)
(2x+2z)(2y)
4xy+4yz