Question

please please solve the abive wuestion whose,answer is 2x^2+8y^2+2z^2+4xz

Answer 1

Hope it helps you !!

Answer 2

We know that,
(a+b+c)²=a²+b²+c²+2ab+2bc+2ac
Now we have,
=(x+2y+z)²+(x-2y+z)²

=x²+4y²+z²+4xy+4yz+2xz+x²+4y²+z²-4xy-4yz+2xz

=2x²+8y²+2z²+4xz.

Hence,
(x+2y+z)²+(x-2y+z)²=2x²+8y²+2z²+4xz