Specific SAT Math Question

Test Preparation
1

<p>Hi, I was doing the 2009 SAT Practice Exam</p>

<p><a href="http://www.collegeboard.com/prod_downloads/sat/sat-preparation-booklet.pdf%5B/url%5D"&gt;http://www.collegeboard.com/prod_downloads/sat/sat-preparation-booklet.pdf&lt;/a> </p>

<p>and I need help on Section 8 number 11. </p>

<ol>
<li>Which of the following is the graph of a function f such
that f x 0 for exactly two values of x between
5 and 5 ?</li>
</ol>

<p>Thanks (refer to picture by clicking on the link)</p>

2

<p>The function equals zero when the graph touches the x-axis. This happens three times for (C), so that can’t be an answer. It happens twice for (D), though.</p>

3

<p>I think you mean “f(x) = 0 for exactly…”.</p>

<p>You can interpret that question as “Which graph touches the x-axis twice from x = -5 to x = 5?”, since the x axis is the line y = x, where f(x) = y. If you can’t see it immediately, try a process of elimination:</p>

<p>A) doesn’t touch x-axis at all, so not A
B) touches x-axis once, so not B
C) touches x-axis three times, so not C
D) touches x-axis two times, so the answer is D
(you can check this if you really want to be sure) E) touches x-axis once, so not E</p>

<p>So the answer is D. Hope this helps!</p>

<p>EDIT: Whoops, beaten to it.</p>

4

<p>Oh I see, Thanks SilverTurtle :)</p>

5

<p>Confirmation that the Hg-turtle moniker was apropos. :)</p>