SAT Question of the Day - Math question

Test Preparation SAT Preparation
1

<p>This is an older SAT question of the day (copied and pasted).</p>

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<p>If x over 3 = x^2, the value of x can be which of the following?</p>

<li>–1 over 3</li>
<li>0</li>
<li><p>1 over 3</p></li>
<li><p>A I only</p></li>
<li><p>B II only</p></li>
<li><p>C III only</p></li>
<li><p>D II and III only</p></li>
<li><p>E I, II, and III</p></li>
</ol>

<p>Correct Answer: D</p>

<pre><code>* Here’s Why:

Roman Numeral Answer Format

Roman Numeral I: Can the value of x be –1 over 3?

You could test this answer by substituting –1 over 3 for x in the equation and seeing whether the result is true. But you can also reason this question out without substituting numbers:

If x = – 1 over 3, then negative 1 over 3 squared within parenthesis is a positive number, because any nonzero number squared is positive.

If x = –1 over 3, then x over 3 is negative.

So x over 3 is negative and x2 is positive.
Therefore, x cannot be –1 over 3.
</code></pre>

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<p>The answer is II and III only, but I thought it was I, II and III. In the explanation above, why did they put the the minus outside the parenthesis? shouldn’t it be (-1/3) squared, with the negative inside?</p>

2

<p>Lol. They did square the negative 1/3. Look at the left side. (-1/3)/3 does not equal (-1/3)^2 simply because the left side is negative while the right side is positive.</p>

3

<p>Haha, thanks...lol @ my temporary lack of intelligence.</p>

4

<p>its alright. I think I got that question wrong the first time I tried it. =]</p>

5

<p>I love questions like these because I'm good with brackets and I can just use a calculator :P</p>