<p>I always get messed up these type of annoying problems that test relationships. This was question #1 and i spent 2 minutes on it and got it wrong. I always have to plug in numbers and do alot of messy stuff to work these.</p>
<p>Can someone offer some advice?</p>
<p>Problems like r-s> r+s</p>
<p>What about it? What is the question? lol</p>
<p>IF you want to prove r - s > r + s, make s negative.
Lets make r = 4 and s = -4.</p>
<p>4 - (-4) > 4 + (-4)
8 > 0, hence we proved it. Is that what you want?</p>
<p>no they give you choices like</p>
<p>a) r > s
b) s < 0
c) r < 0
d) r < s
e) s > 0</p>
<p>I got this one wrong because I was careless. I just want to know how do you guys approach annoying problems like this.</p>
<p>Well I would do what I did above, that eliminates c, d, and e. And I'm left with a and b. Therefore, I pick different numbers until I get one of those out. Lets choose r = -4 and s = -1 </p>
<p>r - s > r + s
-4 - (-1) > -4 + (-1)
-3 > -5
Therefore, we eliminated a, so the answer is b).
Yeah I always play with numbers, eliminate some choices, and then try to prove one of the others wrong by logical brute force.
But, I think someone has better methods than me.</p>
<p>don't bother with numbers. subtract r from both sides and you get -s<s Clearly, S must be negative, thus b is the correct answer. That's how i'd do it at least</p>
<p>r-s> r+s
then 0>2s
0>s</p>
<p>Can be done within 10 seconds if you understand the nature of inequalities.</p>