BB Math Problem Answer Explanations I couldn't find in sticky thread.

Test Preparation SAT Preparation
1

<p>SAT Math Test Section 3:</p>

<h1>10. Page 398.</h1>

<p>If 4 less than 3 times a certain number is 2 more than the number, what is the number?
a. -1
b. -3
c. 1
d. 2
e. 3</p>

<h1>14. Page 399.</h1>

<p>In the xy plane, the equation of line l is y = 2x+5. If line m is the reflection of line l in the x-axis, what si the equation of line m?
a. y=-2x-5
b. y=-2x+5
c. y=2x-5
d. y= -1/2x-5
e. y=-1/2x+5</p>

<h1>15. Page 399.</h1>

<p>The graph above shows Elina's height in inches from the age of 6 to the age of 12. Elina's height at the age of 12 was what percent greater than her height at the age of 6?
a. 15%
b. 25%
c. 33.3%
d. 50%
e. 66 2/3%</p>

<h1>17. Page 399.</h1>

<p>If a + 2(x+1) = s, what is x+1, in terms of s and a?
a. s/2a
b. s-a/2
c. s+a/2
d. s/2-a
e. s/2+a</p>

<h1>18. Page 400.</h1>

<p>The shaded region in the figure above is bounded by the x-axis, the line x=4, and the graph of y=f(x). If the point (a,b) lies in the shaded region, which of the following must be true?</p>

<p>a. i only
b. iii only
c. i and ii only
d. i and iii only
e. i, ii, and iii</p>

<p>SAT Math test section 6:</p>

<h1>6. Page 409.</h1>

<p>Which of the following tables shows a relationship in which w is directly proportional to x?</p>

<p>Answer choices consist of a bunch of charts let me know if you need me to type them. I am pretty sure you can look in the book and see for yourself though. however, if not please let me know and I'll try my best to type the charts out.</p>

<h1>12. Page 411.</h1>

<p>the sum of 5 consecutive intergers is 1000. What is the value of the greatest of these intergers?</p>

<p>SAT Math test Section 9:</p>

<h1>8. Page 425.</h1>

<p>If x squared + y squared = 73 and xy = 24, what is the value of (x+y) squared?
a. 73
b. 97
c. 100
d. 121
e. 144</p>

<h1>11. Page 426.</h1>

<p>In the figure above , rectangele abcd is made up if seven nonoverlapping rectangles. The two smallest rectangles have the same area. Each of the other rectangles has twice the area of the next smaller rectangle. The area of the shaded rectangle is what fraction of the area of rectangle ABCD?
a. 1/128
b. 1/64
c. 1/32
d. 1/16
e. 1/7</p>

<h1>12. Page 426.</h1>

<p>If 2x is less than y is less than 0, which of the following is the greatest?
a. -2x
b. -(2x+y)
c. 2x
d. 0
e. -y</p>

<p>That's all folks. Please help me out here.</p>

2

<p>10) 3x-4=2+x solve</p>

<p>14) reflection of the x axis means f(x)=-f(x). Pick any number for m. and try that number you picked and put into answer choices. Your answer should be the negative of the value of f(x)</p>

<ol>
<li><p>percent greater = final-original/original. Most people wuold proably do 60-45/60, which is wrong. you can always check by taking your fractonal answer, multiply it by the original, and then add the orginal back.</p></li>
<li><p>SAT math is smart manipluatoins. Just move the a to the other side, and divide by 2. You are never really ever reqruired to do complex tedious algebra.</p></li>
</ol>

<p>18) This problem takes logical thinking. YOu know the maximum y value on teh graph is 4. and its lowest is 0. SO you know I is correct.</p>

<p>To check II, try to find a point in the shaded region where the b coordinate is bigger than the corrisponding x coordinate. You will find one around 3, which proves II false</p>

<p>III. is asking about the graph, which represents the curving line. Pick a point. Lets say x=2 it looks like f(2) and 2 are equal. That proves part of III. Lets try another point, say x=3 f(3)~3.5, which is greater than 3. so III is true</p>

<p>this is a diffficult problem, so study the q and e thorughloy</p>

3

<p>12) X+(x+1)+(x+2)+(x+3)+(x=4)=1000</p>

<p>8(x+y)^2=x^2+2xy+y^2. You know what xy is, and you know x^2+y^2 is. Work it out</p>

<p>11) ABCD is your rectange. If you split it in half you get a square, which is the right part of the picture. Split that in half you get the size which is the bottom right of the picture. Split that in half and you get the size which is the bottom bottom right if the picture. Split that in half and half, and you will eventualy get the size of the shaded portion. The shaded region can be represented as 1/2^6, which is 1/64 the size of the main rectange</p>

<ol>
<li>you know that both x and y are negative numbers since they are both less than zero. If you add two netative nubmers togehter, you get an even bigger negative number. like (-3+-2)=-5. And if you multiply a negative times a negative, you get a postitve. Chocie A is also a positive number, but it is not as big since you did not add two negative numbers together.</li>
</ol>

4

<p>oh and for that directly proprtional problem.</p>

<p>Directly proportinal means, that something was multiplied by each succseive term of x to get a y value. So it has to be D. None of the other answers do you have succseive terms multiplied all by the same value produce the numbers in the x column</p>

5

<h1>12. Page 411. the sum of 5 consecutive intergers is 1000. What is the value of the greatest of these intergers?</h1>

<p>200*5=1000, so the numbers must average to 200. The series of numbers 198, 199, 200, 201, 202 does this, and there cannot be a series with a larger highest number because they numbers must consecutive. So it's 202.</p>