SCORE:
-Section 1:16/20
-Section 2:12/16
-Section 3:15/18
INCORRECT ANSWERS:
-Section 1
One of them was a careless mistake so i just wont mention that.
1. If x^3=y^9, what is x in terms of y?
*Square root y
*y squared
*y cubed
*y^6
*y^12
Well the general rule for division is to subtract. So i did, and i got y^6, but the actual answer is like y^6?
2. If k, n, x, and y are positive numbers satisfying x ^-4/3=k^2 and y^4/3 = n^2, what is xy^-2/3 in terms of n and k?
*1/nk
*n/k
*k/n
*nk
*1
I was confused with everything, my main problem being negative & fractional exponents.
3. The figures above show the graphs of the functions f and g. The function f is defined by f(x) =x^3-4x. The function g is defined by g(x)=f(x+h)+k. where h and k are constants. What is the value of hk?
*-6
*-3
*-2
* 3
* 6
Okay, so i found out what f(x) = x^3-4x was, and it was -3. But then i put that in the other equation and i was not sure where to get the h and the k from?
-Section 2:
One of them was a careless mistake so yeah.
1. If a and b are positive integers and a^2 -b^2 =7, what is the value of a?
*3
*4
*5
*6
*7
I broke it down to (a+b)(a-b)=7, meaning that a-b had to equal 7 in one of the cases. 7 was the only integer in which b would be positive. Suppose that a was 6 then b would have to be -1, but since both integers have to be positive, i thought that b couldn't be anything under 7?
2. In the xy coordinate plane, line m is the reflection of line l about the x axis. If the slope of line m is -4/5 what is the slope of line l?
*5/4
*4/5
*1/5
*-4/5
*-5/4
Since it's a reflection, shouldn't the slope still be constant?
3.
I tried a bunch of things and got like 3.
-Section 3
Two of these were careless mistakes so i wont mention them.
18. The average (arithmetic mean) of the test scores of a class of p students is 70 and the average of the test scores of a class of n students is 92. When the scores of both classes are combined, the average score is 86. What is the value of p/n?
I don't know how to set up this equation
1 comment:
1) Opal, that is the general rule for division when the base of the exponents are the same.
X^9/x^3 = x^6. When they're not the same, it doensn't work. 2^9/1000000^3 is not going to equal 2^6.
In this case, you need to take the cube root of each. That leaves you with x=y^3
2) Opal, you need to learn negative fractional exponents. Once you do that, this is very very very simple-- just like an algebra expression
Please read through this
http://oakroadsystems.com/math/expolaws.htm
3) Don't worry about this. You'll learn it in Algebra 2 this year.
4) (A-B)*(A+B)=7. That means that either A-B or A+B must equal 7, and the other must equal 1. You can solve that, and it gives you 3 and 4. You had everything set up-- just didn't finish. No worries-- you got the hard part there. Just stick with it and keep practicing.
5) The slope isn't constant. Draw the reflection out. You'll see. Reflections across the x axis have negative versions of the same slope. Reflections across the Y axis have negative and inverse versions of the same slope. Please draw this out and you'll see.
6) you set this up like this:
that function of (a)= a^2-a
that function of (a-2)= (a-2)^2-(a-2)
set those equal
a^2-a = (a-2)^2-(a-2)
Thats it. solve that equation. A bunch of stuff cancels out and you get an answer that is correct. try it
7) Thats ok-- averages are tricky to set up. You can imagine that every student in class P got a 70, and every student in class N got a 92.
Thus, the equation for the average in class 1 is:
p*70 / p= 70
P*70 is the sum of all of the students in the class getting 70s. the p in the denominator is dividing by the total # of students in the class. and the 70 is the average.
The same is true for N
(92*N)/N=92
Thus, when we want to calculate the average for both classes, you can't just combine them straight up. You have to use the formula-- (sum of scores)/total students = average
(70*P+ 92*N)/(P+N)= 86
Then you just need to solve to get a ratio for P/N or whatever it is. That is something you can do with that equation.
Good work!
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