Question

Please sir Ji questions numbers 12

Answer 1

check krke batao yahi h kya proof

Answer 2

=x^2+y^2+2xy-2yz-2zx
=(x^2+y^2+2xy)-2(yz+zx)
=(x+y)^2-2[z(y+x)].
(we can write y+x as x+y also)
=(x+y)^2-2[z(x+y)]
=(x+y)[x+y-2(z)]
=(x+y)(x+y-2z)

your answer is (x+y)(x+y-2z)
hope it will be correct