SECTIONS:
1. First SAT Test, Math Section 3
2. Third SAT Test, Math Section 1
SCORE:
1. 13/20
2. 18/20
INCORRECT ANSWERS:
*FIRST SAT TEST MATH SECTION 3*
I am not going to list them, but i had three careless mistakes in this chapter that are all not a big deal.
1. If x^2 + y^2 =73 and xy=24, what is the value of (x+y)^2?
How to i break up x^2+y^2=73?
2. If (a+b)^(1/2)= (a-b)^(-1/2), which of the following must be true?
* b= 0 (zero)
*a+b=1
*a-b=1
*a^2 +b^2 =1
*a^2-b^2=1
I understood how to break down (a+b)^(1/2)
into a square root sign but i'm still not completely clarifyed on a negative square root. This weekend, when i am completely free ( as i won't have any work to do and no friends to catch up with) I will spend my extra time trying to learn everything (functions, negative square roots)
3. The figure above shows the graphs of y=x^2 and y=a-x^2 for some constant a. If the length of line PQ is equal to 6, what is the value of a?
*6
*9
*12
*15
*18
My problem is i don't get this diagram & i have never seen anything like it.
4. Set X has x members and say Y has y members. Set Z consists of all members that are in either set X or set Y with the exception of the k common members (k>0). Which of the following represents the number of members in set Z?
*x+y+k
*x+y-k
*x+y+2k
*x+y-2k
*2x+2y-2k
I just don't understand any of this problem. I have thought about it but mainly i am puzzled at "k>0". What does that mean??
*THIRD SAT TEST, MATH SECTION 1*
1. For which of the following functions is f(-3)>f(3) ?
*f(x)=4x^2
*f(x)=4
*f(x)=4/x
*f(x)=4-x^3
*f(x)=x^4+4
My fundamentals are screwed up. I will study functions this weekend.
2. A total of k passengers went on a bus trip. Each of the n buses that were used to transport the passengers could seat a maximum of x passengers. If one bus has 3 empty seats and the remaining buses were filled, which of the following expresses the relationship among n, x and k?
*nx-3=k
*nx+3=k ~
*n+x+3=k
*nk=x+3
*nk=x-3
I filled in numbers again. I used 23 for k, 4 for n and 5 for x. My answer was~.'
1 comment:
For #3 above...
At points P and Q, the value of y must be the same for both equations because the lines are at the same point.
That means x^2 = y = a - x^2 at P and Q.
I could just take the y out of that previous expression, and I would have x^2 = a - x^2.
Solving for a, I get a = x^2 + x^2.
Do I know what x is at points P and Q? Yes. They told me that the line between P and Q is equal to 6, so the distance from the y axis to point P is 3 (which would mean the value of the x coordinate at that point is -3). In the same way, the value of x at point P equals 3.
Now we can plug in 3 (or -3) into our equation a = x^2 + x^2 to solve for a. a = 9 + 9 = 18, answer (E).
I post more solutions, as well as SAT tips and study tips over at my blog, www.studyprof.com
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