<p>i don't get the following questions:</p>
<p>pg. 656 # 12
pg. 657 # 15,18</p>
<p>pg. 673 #16
pg. 674 #19, 20</p>
<p>pg. 684 #16</p>
<p>thnxs =]</p>
<p>You can find all but 656/12 in <a href="http://talk.collegeconfidential.com/sat-preparation/339734-consolidated-list-blue-book-math-solutions-3rd-ed.html%5B/url%5D">http://talk.collegeconfidential.com/sat-preparation/339734-consolidated-list-blue-book-math-solutions-3rd-ed.html</a></p>
<p>The graph is y=ax^2 and we're told that the perimeter of PQRS is 10. Add the sides up and you will find that R is at 1,3 and s is at -1,3 . Lets plug R into the equation.</p>
<p>3=a(1^2)
3=a1
a=3</p>