Question

plz help guys ... and answer shoup be shown properly

Answer 1

x=1
y=2
z=3
x+y+z=6
=1+2+3
=6
${1}^{2} + {2 }^{2} + {3}^{2}$
=14
xy+yz+xz
1×2+2×3+1×3
2+6+3=11