math 2 subject test question question from sparknotes

<p><a href="http://s24.postimg.org/i8v0ssjh1/campture.png%5B/url%5D"&gt;http://s24.postimg.org/i8v0ssjh1/campture.png&lt;/a&gt;&lt;/p>

<p><a href="http://s12.postimg.org/ld343sxgt/Capture.png%5B/url%5D"&gt;http://s12.postimg.org/ld343sxgt/Capture.png&lt;/a>
<a href="http://s22.postimg.org/6f2dzdrs1/Capture.png%5B/url%5D"&gt;http://s22.postimg.org/6f2dzdrs1/Capture.png&lt;/a>
<a href="http://s29.postimg.org/6dsauxd4n/Capture.png%5B/url%5D"&gt;http://s29.postimg.org/6dsauxd4n/Capture.png&lt;/a&gt;&lt;/p>

<p>how do I solve these?</p>

<p>I managed to solve the middle 2
I just need help in the first and the last question</p>

<p>x<em>3 = 4
x</em>4 = 6</p>

<p>x<em>4 = x</em>2 + 4
6 = x<em>2 + 4
x</em>2 = 2</p>

<p>x<em>3 = x</em>1 + 4
4 = x<em>1 + 4
x</em>1 = 0</p>

<p>x<em>1 = 0; x</em>2 = 2; x<em>3 = 4; x</em>4 = 6
this is an arithmetic progression with the first term(a) = 0 and common difference(d) = 2</p>

<p>x_n = a + (n-1)d
= 0 + 2(n-1)</p>

<p>x_2 = 2</p>

<p>x<em>n / x</em>2 = 2(n-1)/2 = n-1</p>

<p>the last one has already been discussed here
<a href=“http://talk.collegeconfidential.com/sat-subject-tests-preparation/1586436-math-level-2-questions.html[/url]”>http://talk.collegeconfidential.com/sat-subject-tests-preparation/1586436-math-level-2-questions.html&lt;/a&gt;&lt;/p&gt;

<p>Thank you so much. I really appericate your help!
I am sorry I tried searching for the answers first on google but I guess somehow I missed the 4th one. Thank you so much once again</p>