1a) $(x,y,z) = (0,y,0)$ for arbitrary $y$
1b) $(x,y,z)=(x,0,z)$ for arbitrary $x$ and arbitrary $z$
2a) $\sqrt{1+25+1} = \sqrt{27}$
2b) $\sqrt{49+16+9} = \sqrt{74}$
3a) $4+10+18 = 32$
3b) $-35 + 64 - 36 = -7$
4a) $< -3,6,-3 >$
4b) $< -3,1,5 >$
5a) $x_1^2 + x_2^2 + x_3^2$
5b) $\vec{x} \cdot \vec{x} = |\vec{x}|^2$ (OR $\sqrt{\vec{x} \cdot \vec{x}} = |\vec{x}|$)
5c) Direct computation and comparison
6) $\frac{\pi}{4}$ radians (also known as $45^o$, but don't use degrees in calculus!)
7a) $(3,1,0)$
7b) $(0,1,-4)$
8) center: $(1,2,3)$ radius: $1$