Some Math and Writing Questions from practice tests!!!

Test Preparation SAT Preparation
1

<p>Im taking the SAT next saturday and im doing a bunch of practice tests from the college board book. Too bad they don't give explanations. Anyways you do not have to answer every single question i post here but I would appreciate any help you can provide. Here are the problems that I came across that I do not get-</p>

<p>1 (level 4 question). Several values of the function f are shown above-
X 2 3 4 5 6 7 8<br>
f(x)-1 0 2 -3 4 -5 6 (its supposed to look like a chart btw)</p>

<p>The function g is defined by g(x) = f (3x+1). What is the value of g(2)? </p>

<p>Answer is -5. Please explain. And overall whenever i see a function problem on the SAT I panic because i simply just dont understand them!!</p>

<ol>
<li>Any 2 points determine a line. If there are 6 points in a plane, no 3 of which lie on the same plane, how many lines are determined by pairs of these 6 points? </li>
</ol>

<p>Answer is 15. Please explain (level 4 question)</p>

<ol>
<li>A certain function f has the property that f(x+y)= f(x)+ f(y) for all values of x and y. Which of the following must be true when a=b? </li>
</ol>

<p>I. f(a+b) =2f(a)
II. f(a+b)= [f(a)]^2
III. f(b)+ f(b)= f(2a)</p>

<p>Answer is I and III only</p>

<ol>
<li>In the equation above- (x-8) (x-k)= x^2-5kx +m
k and m are constants. If the equation is true for all values of x, what is the value of m? (level 5 difficulty)</li>
</ol>

<p>Answer is 16</p>

<ol>
<li>In the xy- plane, the line 2x-3y=c passes through point (5,-1). What is the value of c? (only level 3 difficulty) </li>
</ol>

<p>Answer= 13</p>

<p>Writing questions-</p>

<ol>
<li>A volunteer organization, the Covington Soup Kitchen has been feeding needy families since 1977, annually distributing nearly a million pounds of food each year. </li>
</ol>

<p>Apparently the error is in "each year"?????? How? </p>

<p>Also can someone go over when to use has versus have and when to use their vs its?</p>

<p>I dont expect 1 person to answer all these questions obviously so any little help would be greatly appreciated.. thank you!!!</p>

2

<p>This is pertaining to the grammar question.</p>

<p>Since the word annually is already written, there is no need for “each year” since annually means: yearly (or every/each year).</p>

3

<ol>
<li>g(2) = f (3*2+1) = f (7)
Go to the chart and find where x is 7:
-5
When putting things in, just replace x with he number.</li>
</ol>

<p>5.
Put the coordinate into the equation:
2(5) - 3(-1) = c
10 - (-3) = c
10 +3 = c
c=13</p>

4

<p>Thank you! Way simpler than i made them out to be, now just 2,3,4 ( 4 seems reallyyyy hard…lol)</p>

5

<p>Oh my, I tried four… and got the wrong answer :p</p>

<p>I’ll try to explain three though:</p>

<ol>
<li>A certain function f has the property that f(x+y)= f(x)+ f(y) for all values of x and y. Which of the following must be true when a=b? </li>
</ol>

<p>I. f(a+b) =2f(a)
II. f(a+b)= [f(a)]^2
III. f(b)+ f(b)= f(2a)</p>

<p>I. f(a+b) = 2f(a)
Rules for f say f(x+y) = f(x) + f(y)
So: f(a+b) = f(a) + f(b)
Since a =b, then we have f(a) + f(a) = 2f(a)
Thus I is true.</p>

<p>II. f(a+b)= [f(a)]^2
This one makes no sense whatsoever.
f(a+b) = f(a) + f(b) = f(a) + f(a)
There is nothing about multiplying those together that could give that squared.</p>

<p>III. f(b)+ f(b)= f(2a)
since a=b, then
f(a) + f(a) = 2f(a)
Like I, rules say f(x+y) = f(x) + f(y)
So: 2f(a) = f(a) + f(a) = f(a+a)
True.</p>

6

<p>Sorry I just dont understand it, this might be the dumbest question ever but what exactly is a and b? uhh i hate this question in general</p>

7

<p>Hm…well, they are just… two equal variables :stuck_out_tongue:
Try placing a number in and see if it helps.
Say a = 5. Thus b = 5 also.</p>

8

<ol>
<li>In the equation above- (x-8) (x-k)= x^2-5kx +m
k and m are constants. If the equation is true for all values of x, what is the value of m? (level 5 difficulty)</li>
</ol>

<p>x^2 - kx - 8x + 8k = x^2 - 5kx + m
x^2 - x(k +8) + 8k = x^2 - 5kx + m</p>

<p>k + 8 = 5k
8k = m</p>

<p>k = 2; m = 16</p>