<p>In the blue book, pg. 412, numbers 17 and 18. Thanks</p>

<h1>17.</h1>

<p>(0,p) and (5,t) are the points given and x=y^2-4 is the equation given correct? So since we know the x coordinates for both points, we can plug them in the equation to get the possible y coordinates (p and t).</p>

<p>0=y^2-4

y^2=4

y= +/- 2</p>

<p>5=y^2-4

9=y^2

y=+/- 3</p>

<p>So there are 4 different combinations you could use to see which has the greatest slope.</p>

<p>you could try all 4 of them, but it would be easier if you knew that the largest positive number (in this case 3) - the negative of the other number will get you the greatest slope.</p>

<p>(3--2)/(5-0)= 5/5=1</p>

<p>Ah, I see. Thanks a lot. I'm such an idiot, I forgot to do +/- so the answer I got was 1/5.</p>

<h1>18</h1>

<p>let x be the time:</p>

<p>30x = 45 * (1-x) 1 for one hour</p>

<p>solve for x</p>

<p>x = 0.6 </p>

<p>distance = speed * time

30 * 0.6 =18</p>