Two SAT Math problems I need help with

<p>1) A square sheet of paper with area 49 is to be folded in half to make a rectangle. What is the perimeter of this rectangle?</p>

<p>2) For all x is not equal to 5, the expressio n 2x^2 + 8x- 10/x^2 - 25 equals</p>

<p>A) 2x + 1/x + 5
B) x - 1/x - 5
C) 2x - 1/x + 5
D) 2x - 2/x - 5
E) x - 1/x + 5</p>

<p>first is 21. long sides will still be 7. folding it cuts the other sides to equal half of 7. Together they are 7. 7+7+7= 21.</p>

<p>I don’t get what the second question is even asking. Sorry.</p>

<p>For question one, each side of the square is equal to sqrt(49) which is 7.
Folding that in half gives two sides of length 7 and two sides of length 7/2 (which is 3.5).
So the perimeter is 7 + 7 + 3.5 + 3.5 = 21.</p>

<p>For question two, I noticed that you forgot to add the brackets. The question is written as:</p>

<p>(2x^2 + 8x -10)/(x^2 - 25)</p>

<p>The answer is (D)</p>

<p>Here’s how I did it:
(2x^2 + 8x -10)/(x^2 - 25)</p>

<p>= (2x^2 + 10x - 2x -10)/(x^2 - 25)</p>

<p>=(2x(x+5) - 2(x+5))/((x+5)(x-5))</p>

<p>=((2x-2)(x+5))/((x+5)(x-5))</p>

<p>Cross out (x+5) at the top and bottom and you get:</p>

<p>(2x-2)/(x-5)</p>

<p>Hope that helps :)</p>

<p>Yeahhhh I was thinking the brackets were missing. I was like… this makes NO sense. aha</p>

<p>Yeah I saw it the first time and tried without brackets and I got this:</p>

<p>(2x^4 + 8x^3 -25x^2 - 10)/x^2</p>

<p>lol I was like ***</p>

<p>^To check (or, if you are stumped, to solve) equivalency problems, I commonly just plug in a number. In this case, I can’t plug in 5, so I’d probably put in 3, 4 or 6 (I tend to avoid 0, ±1, and ±2 because that may give two answer expressions that are equivalent). I find out what the function in the statement gives with the desired input, and then I plug the same input into the answer choices. Ideally, there will be one answer choice that gives you the same number as the original function, hence you can be almost certain (human error is a possibility) that you found the two equivalent expressions.</p>