## Calculus 8th Edition

(a) $x+y+z=3$ (b) $\frac{x-1}{2}=\frac{y-1}{2}=\frac{z-1}{2}$
$xy+yz+zx=3 ; (1,1,1)$ (a) Equation for a tangent plane is given as: $z-1=-(x-1)-(y-1)$ $z-1=-x-1-y+1$ $x+y+z=3$ (b) $x+y+z=3$ Equation of normal line is: $\frac{x-1}{2}=\frac{y-1}{2}=\frac{z-1}{2}$