<p>I just took a practice test in the blue book and would like to review over the questions i got wrong (and right) In the book, it just gives the answer but does not provide explanations. Is there anywhere i can get free explanations for each question? Thanks</p>
<p>Yes. Login to your CollegeBoard account, and then click on My Organizer. There is a link to answers and explanations for the Second Edition.</p>
<p>Thanks! Found it :)</p>
<p>Btw can somebody explain #18 in test 1 sec 3 of bluebook. its a function problem.</p>
<p>Mathela, to do that problem you first have to isolate one of the constants (k) in order to find the other (a). Do this by writing:</p>
<p>f(x) = k(a^x)
and then inserting one of the values given for x. Since we’re trying to find the value of one of the constants, we want to get rid of the other one. You can’t do anything to k, but you can get rid of a by using 0 as your x! So…</p>
<p>f(0) = k(a^0)</p>
<p>Or…</p>
<p>f(0) = k</p>
<p>Now, according to the chart, f(0) is the same thing as x-value 1/2. Thus…</p>
<p>1/2 = k</p>
<p>Now we have one of the constants - k! Very helpful. Next step is using the k we just found to find a. Back to the original equation…</p>
<p>f(x) = k(a^x)</p>
<p>We can now insert an x-value from the chart that won’t get rid of a. -1 is gross and gives us a fraction, so let’s just use 1. </p>
<p>f(1) = k(a^1)
f(1) = k(a) </p>
<p>You might say, “Well that doesn’t help anything!” But in fact… it does! According to the chart, inserting the x-value 1 into f(x) - f(1) - gives you 2. So we know…</p>
<p>2 = ka </p>
<p>The great thing is, we solved for k earlier - it’s 1/2! So we insert that…</p>
<p>2 = (1/2)a
2/(1/2) = a
a = 4</p>
<p>And there’s our answer.</p>
<p>I pretty much wrote this out to explain the problem to myself, but if anyone else benefits from it, cool! haha :)</p>
<p>thanks so much! Very helpful! I know I’m a newby, so my opinion wont matter as much, but maybe we should have an official blue book answers explained section? Just thought of that.</p>
<p>NP! You can actually find the explanations for the Blue Book questions (2nd edition) here: [Welcome</a> to the Official SAT Study Guide Book Owner’s Area](<a href=“SAT Study Guide – SAT Suite | College Board”>SAT Study Guide – SAT Suite | College Board) They’re short but easy to understand. I just went way overly in-depth with mine for the sake of being easy to follow :)</p>
<p>Thanks peachie. A few days ago, I found the explanations section but for some reason, I couldnt get to it yesterday. So i just bookmarked the link :)</p>