<p>x^.5 + x^.25 = 20</p>
<p>What is/(are) the solution(s)?</p>
<p>Very, very tricky problem that I made even more difficult. Not an "SAT" problem, persay. I ended up having to solve it by brute force when I did it.</p>
<p>Let x^0.25 be y
y^2 + y = 20
y = -4(reject) or 5
X = 5^4 = 625</p>
<p>^you found the right method…but check your factoring – you have the minus signs flipped. That’s why when you go check your solution: 625^.5 +625^.25 it comes out to 30, not 20…</p>
<p>But your method was correct.</p>
<p>The original source considered 625 to be an answer because
625^.5 + 625^.25 =
25 + (-5) = 20</p>
<p>I’m not sure if that would actually be considered a solution on a standardized test…</p>
<p>I actually thought both could work too…
._.</p>
<p>Both seem to work.</p>
<p>Notice I said <em>an</em> answer.</p>
<p>The answers are 256 and 625 according to the original source.</p>
<p>What was the original source?</p>
<p>Because not that it matters, but 625^(1/4) is only 5, not -5, by definition. It’s true that 5 and -5 are both solutions to the equation x^4=625. </p>
<p>It’s just like how x^2=2 has two solutions: +sqrt(2) and -sqrt(2). But sqrt(2) itself is by definition positive. And x^2=9 has two solutions: +sqrt(9) and -sqrt(9) or 3 and -3. But sqrt(9) is defined as the positive root.</p>
<p>This is certainly nitpicking, but the SAT will definitely get this right.</p>
<p>It was from an unofficial IQ test that I was taking for giggles. Taking an IQ tests sounds extremely vain now that I’m saying it 
…</p>
<p>^^</p>
<p>i was in this very serious mood, read this, and just started laughing lol…</p>
<p>P.S. I took once too… It is vain. :PP</p>
<p>but again the fact the SAT itself is sometimes thought of as an IQ test made me stop laughing… -_-</p>
<p>It just makes you think…
hmmmmm…</p>
<p>Pffft 2400? I can get that on an IQ test.</p>
<p>But yeah I feel like an ass for taking an IQ test. On the bright side, I did learn the words brobdingnagian, ailurophile, tergiversation, eleemosynary, and autochthonous in the process.</p>