<p>Well, instead of making several threads, I thought I would combined several questions into one. First, I was going through the Kaplan "Subject Test: Mathematics level 2 2008-2009 Edition" and I can't see how they got the answer on page 163 example 4 - is it their mistake, or mine? They claim the answer is a), while I don't see an answer that works.<br>
Also I know Barron's has a reputation for being harder than the actual test - is Kaplan the same way?</p>
<p>Maybe you could post the example 4 question.</p>
<p>The question is about the a function:</p>
<p>p(x) = absolute value of (2-X) + 1/2</p>
<p>if y = p(x) then which of the following could be the graph?</p>
<p>the “answer” a) starts out with a positive y value when x = 0, and then increases as the absolute value of x increases</p>
<p>the answer I got wasn’t even a choice, b) was pretty close, but it had a y=0 value, which of course can’t happen… </p>
<p>Hope I explained it well enough! :)</p>
<p>As the absolute value of x increases, so does |2-x|</p>
<p>e.g.
x = -1: |-1| = 1 and y = |2 - (-1)| + 1/2 = |3| + 1/2 = 3.5
x = -5: |-5| = 5 and y = |2 - (-5)| + 1/2 = |7| + 1/2 = 7.5</p>
<p>x = 3: |3| = 3 and y = |2 - 3| + 1/2 = |-1| + 1/2 = 1.5
x = 7: |7| = 7 and y = |2 - 7| + 1/2 = |-5| + 1/2 = 5.5</p>
<p>How? |2-0|+ 1/2 > |2-2|+ 1/2</p>
<p>So while |2-x|does generally increase when|x|increases, that isn’t always the case. Basically, the graph they give as the solution increases as |x|increases - it starts out at x=0, y = 2.5 (0, 2.5) </p>
<p>(|2-0|+ 1/2 = 2.5) </p>
<p>and then slopes up wards both left and right. What I’m saying is that it should in fact go down when (x=1, x=2, or x=3), and then when x=4 y = 2.5 again… </p>
<p>I even punched it ( y=abs(2-x)+.5 ) into my TI-84 and got a graph not given as an answer…
Any thoughts?</p>
<p>Practice tests from any source other than the test-maker are flawed. Choose the best answer, even if the best answer isn’t always right, I guess. Doesn’t quite answer you question, but oh well…</p>
<p>Yeah, I try not to do practice tests other than the college board’s, but this was just an question in a review section - It baffles me how a company doesn’t catch such mistakes, before publishing.</p>