From: Nathan Dunfield <nathand@math.harvard.edu>
To: Math 20; 

Here are the "back of the book" answers for the review problems without
back of the book answers, and for which the "answer" is not contained 
in the problem itself.  

11.3 #34:  (a) III , K, (b) V, G (c) IV , J (d) I. H (e) II, F

13.3 #8:  9 + 6 x + 9 y

13.4 #7:  The region where x > 2

13.5 #34 a) (-4, 4, 2).  b) 24

13.5 #36 a) (0, 0), 100   
	b)  (-3, -2) [any pos. multiple of this vector is correct]
	c)   (3, 2)     [same comment]
	d)    yes
	e)    (-2, 3)
	f)    circles
	
13.7 #26:  Neg Pos Pos Pos Neg