Math problems: need explanation

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1

<p>Maybe because I’m extremely tired, but these Collegeboard explanations are not making any sense:</p>

<p>Math problem #1 : <a href=“http://i7.■■■■■■■■■■■■■■■/albums/y251/sleppy/lolsat2.jpg[/url]”>http://i7.■■■■■■■■■■■■■■■/albums/y251/sleppy/lolsat2.jpg&lt;/a&gt; – How did they get 4/5k?</p>

<p>Math problem #2: <a href=“http://i7.■■■■■■■■■■■■■■■/albums/y251/sleppy/sAtwow.jpg[/url]”>http://i7.■■■■■■■■■■■■■■■/albums/y251/sleppy/sAtwow.jpg&lt;/a&gt; – Where did they get the 8t from?</p>

2

<p>For #2, they get the 8t from squaring the (t-4)^2 = t^2 -8t + 16 (as they show you). So now t + 16 = t^2 -8t + 16
t = t^2 -8t</p>

3

<p>for #1
They say that this year’s amount was K
and thats a 25 percent increase from last year</p>

<p>so actually this years amount is (1.25)(percentage of k last year) which equals 1k</p>

<p>so you solve the equation (1.25)x=1 to get the percentage of k that existed the year before</p>

<p>x=.8</p>

4

<p>yeah, I understand #1, just didnt know where they got that 4/5…</p>

<p>but for #2, i still dont understand where they get the 8 from</p>

5

<p>(t+4)^2 = t - 4t - 4t + 16=t^2-8t+16 </p>

<p>It’s simply squaring a term. The whole “values of t greater than 4” just ensures you don’t have to worry about imaginary numbers.</p>

6

<p>4^2 = 16…? I’m missing the point, I’m feeling dull.</p>

7

<p><a href=“x%20+%20y”>b</a>^2 = x^2 + 2xy + y^2**</p>