Help me answer some math problems!

<p>Hey! I'm doing practice tests that have no answer keys and these problems I had a hard time doing and not sure about them. </p>

<p>The links to the problems are: <a href="http://oi53.tinypic.com/2ahu0dl.jpg%5B/url%5D"&gt;http://oi53.tinypic.com/2ahu0dl.jpg&lt;/a>, <a href="http://oi52.tinypic.com/nqtthk.jpg%5B/url%5D"&gt;http://oi52.tinypic.com/nqtthk.jpg&lt;/a>. </p>

<p>I would really appreciate it if someone solves it and explains how they solved it, thanks in advance!
P.S: What would I do if college-confidential didn't exist?</p>

<p>AC = AD + DC = 6+3 =9</p>

<p>A of triangle ABC = .5(9)(4) = 18
A of triangle DBC= .5(3)(4)= 6</p>

<p>just subtract the second from the first</p>

<p>for the second one:
first I thought about possible combinations of numbers that would have half of a sum exceed the sum–not specific numbers, but rather properties of the numbers.</p>

<p>The only way that could happen in SAT realm (I can’t say in all instances with confidence because I have not taken all the math courses in existence) is if the sum is negative, so half of that sum would be to the right of the sum along hte number line (but still negative)
since the ticks are evenly spaced, I assigned x -6, x+y -4, and x+y/2 -2. (or their multiples [e.g., -600 billion bah bum]) </p>

<p>y would have to be 2, which corresponds with letter E</p>

<p>xiggi might be hiding in the woodworks with a repository containing a previous iteration of this problem and the corresponding analytical solution but I’m rather lazy</p>

<p>Cheers! Great help!!!</p>