<p>Hey, I need some help with a few math problems from the blue book. Thanks in advance. :)</p>
<p>pg 489, #7
pg 490, #12
pg 521, #11 and 14
pg 522, #15</p>
<p>bump....................</p>
<p>pg 489, #7:</p>
<p>x^(-1/2) = 1/ 3
1/sqrt(x) = 1 / 3
So sqrt(x) = 3
x = 9</p>
<p>Now we have y^z = 16
Think of two integers that will fit the above WHILE z is greater than y
That would be 2^4</p>
<p>Thus z = 4</p>
<p>We want x + z
x + z
9 + 4
13</p>
<p>Ans: 13</p>
<p>pg 490 # 12 can be found here:</p>
<p>Pg 521 # 11:</p>
<p>We want to compare the circumferences of the two wheels. The front wheel has half the diameter.</p>
<p>C = pi * d</p>
<p>So for the back wheel:</p>
<p>C = pi * d</p>
<p>For the front wheel:</p>
<p>C = pi * .5 * d
C = .5(pi * d)
C = .5(C of Back Wheel)</p>
<p>So the front wheel has half the circumference. If the back wheel rolls once, the front wheel would have to roll twice in order to cover the same distance.</p>
<p>Pg 521 # 14:</p>
<p>This is a matter of plug and play. We know that the sum has to be LESS than 6. If we use any number greater than 3 for x or y, the sum goes above 6 or reaches it. So we have to use 1s, or 2s. Remember ZERO is NOT positive. A 2 can only be used for x since if we use it for y, the sum will reach 6. So one combination would be (2, 0). We are left with 1s. Both can be one. So another combination is (1, 1)</p>
<p>Ans: 2, which is B</p>
<p>pg 522, #15:</p>
<p>Remember that in a triangle, if two angles are the same, the sides opposing those two sides MUST be the same. In the second triangle we see all the sides are the same. Why? If two of the angles are 60, the third must be also since the sum of the angles equals 180. So all the sides are the same. Meaning the perimeter is 5 + 5 + 5, which is 15. </p>
<p>For the first triangle, the side opposing X is 8. Must there are two Xs in the triangle. The side opposing the OTHER x must also be 8. So the perimeter is 5 + 8 + 8, which is 21.</p>
<p>The difference of the two perimeters is:
21 - 15
This equals 6</p>
<p>The answer is 6, which is C</p>
<p>Thank you so much! I really appreciate it!</p>
<p>The answer to 521 #14 says its A.</p>
<p>You have to use the equation they provide for the ordered pairs and only (1, 4/3) works. Therefore, the answer is one pair or A.</p>
<p>can someone re-explain </p>
<h1>14 pg 521?</h1>
<p>This isn't really clear.</p>
<p>If it says "positive integers", shouldn't you only be able to use 1 and 2?</p>
<p>^Yeah, you can only use positive integers.
Spazattack is wrong, because 4/3 is clearly not an integer. The only ordered pair comprised of positive integers that works is (1,1), since that would equate to 5, making it less than 6.</p>