<p>Here's a few tough ones I couldn't handle, if you figure it out, provide an explanation please!</p>
<ol>
<li><p>If x^2=(ax^2) + 4ax+4a+4 for all positive values of x, which of the following equals a?
a)(x-2)/(x+2)
b)(x+2)/(x-2)
c)(x^2)-4)/4x
d)(x^2)+4)/4x
e) (x^2)-4</p></li>
<li><p>
<a href="http://i41.tinypic.com/15nw0ub.jpg%5B/IMG%5D">http://i41.tinypic.com/15nw0ub.jpg
</a></p></li>
</ol>
<p>3.
<a href="http://i44.tinypic.com/2dmieza.jpg%5B/IMG%5D">http://i44.tinypic.com/2dmieza.jpg
</a></p>
<ol>
<li>
<a href="http://i40.tinypic.com/25u7d6v.jpg%5B/IMG%5D">http://i40.tinypic.com/25u7d6v.jpg
</a></li>
</ol>
<p>Thanks, and hopefully you get good practice out of this haha</p>
<p>I’m done with the SAT but man I still love a good math problem. LOL ><</p>
<p>Anyways:</p>
<p>1.</p>
<p>x^2=ax^2+4ax+4a+4
x^2-4=ax^2+4ax+4a
(x-2)(x+2)=a(x^2+4x+4)
(x-2)(x+2)=a(x+2)(x+2)
a=(x-2)/(x+2)</p>
<p>This one was pretty simple, I did it this way without any other work.</p>
<p>2.</p>
<p>let x= the number of people who watched a movie
110 is the total # of movies watched</p>
<p>then</p>
<p>110=(x-7)+4<em>2+3</em>3 It is x-7 because you know 7 of the people are already accounted for with the watching two movies or three movies info. the 4<em>2 and the 3</em>3 are to account for those people. Basically you know, x-7 people each watched only one movie.
So x=100 (by basic algebra)
Then .2*(total number of people surveyed)=x=100
so (total number of people surveyed)=500</p>
<p>3.</p>
<p>The critical part of this question is the “at least” part.</p>
<p>So you know that 80% of the kids are in “at least” one club. So 460<em>.8=368 students in at least one club. You also know that .6</em>460=276 are in two or more clubs. So:</p>
<p>(students in two or more clubs)/(students in at least one club)=(276)/(368)=75%</p>
<p>4.</p>
<p>Not sure about this one. I’m blaming my failure on my tiredness, LOL.</p>
<p>You might want to try something using these principles:</p>
<p>The maximum coordinate for a quadratic is given by x=-b/2a</p>
<p>Using this and something else you may(may!) be able to solve through, but I’m too tired to do it.</p>
<p>NWskier, thanks for your help! You got 1 and 2 right, I think number 3 is 540 though, but I can see how you got that. </p>
<p>I’m still working out 4, you’re welcome to finish it up whenever you feel rejuvenated haha.</p>
<p>Thanks again!</p>
<p>These are from elite!!
I just took this test last week.
Actually the answer to number 2 is 525.
It’s because the total movies watched is
115. And then you would subtract the people who watched more than one.
So, (115)-(4)-(3)-(3) = 105. These are the people who watched at least 1 movie, which is 20%.
So (105)(5) gives you the total people interviewed. Which is 525.</p>
<p>4) (11,12) IS the vertex of the graph f(x) = -(x+a)^2 - b</p>
<p>The function equation is in vertex form, so plug in the values of the vertex into the equation. (11,12) = (a,b)</p>
<p>f(x) = -(x - 11)^2 +12
f(c) = 8</p>
<p>8 = -(x -11)^2 +12
-12 -12</p>
<p>-4 = -(x - 11)^2</p>
<p>4 = (x - 11)^2</p>
<p>4 = x^2 - 11x -11x + 121</p>
<p>0 = x^2 - 22x + 117</p>
<p>0 = (x - 9) (x -13) </p>
<p>x or c = 9, or 13</p>
<p>Im too sleepy, so sorry if this is unclear.</p>
