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**4littlepiggiesmom****Member**- Registered: 2006-01-09
- Posts: 42

My daughter had to go to music festival today so missed math test. she worked all weekend on the and asked me to look them over which I did but some of these were over my head...so I came here.

1. What is the average rate of change of f(x)=x^3-x in the interval {-2,2}?

a. 6

B. -3 THIS is her answer!

c. 3

d. 0

e. none of these

2. If a+bi is a complex number, llet {a+bi}=(sqrt)a^2+b^2. What is n[(3+4ai)^3]?

a. 625

b.125

c.5

d. (sqrt)91 which is 9

e. none of these THIS is her answer!!!

3. What is the sum of the solutions of 4^x -3 *2^x=2 + 32=0?

a. log^UNDERSCORE 2 (8/3)

b.2 THIS is her answer!

c. 5

D. -5

e. none of these

4. X+Y+Z, wher (x,y,z) is the solutionto the following linear system:

X+2Y+3Z=1

Y+2Z=2

Z=3

a. 7 This is her answer

b. 9

c.0

d. 1

e. none of these

5.Simplify the expression ln(81)+lm(27)+in(9) all over / ln(27)-ln(9) + ln (3)

a. ln(117)/lm(21)

b. 9/2

c. 7ln(3) This is here answer

d. 4.51

e. none of these

hope I wrote these so you can understand them...thanks!

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**George,Y****Member**- Registered: 2006-03-12
- Posts: 1,316

1 i guess is 3 instead of -3 3 = ((8-2) - (-8+2))/(2-(-2))

4 -1 (x+2y+3z)-(y+2z)=x+y+z

5 9/2 = (4+3+2)ln3 / [(3-2+1)ln3]

sorry i can't understand 2 and 3

**X'(y-Xβ)=0**

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**4littlepiggiesmom****Member**- Registered: 2006-01-09
- Posts: 42

#2 should be this..

if a + bi is a complex number, let n[a+bi] = Sqrt (s^2 + b^2). What is n[(3+4i)^3]?

Answers

a. 625

b. 125

c. 5

d. Sqrt (91)

e. none of these

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**George,Y****Member**- Registered: 2006-03-12
- Posts: 1,316

I guess a+bi is any complex number, and n[]is a kind of function that outputs a comlex number's modulus

|a+bi|=Sqrt (a^2 + b^2)

|(3+4i)^3| = |3+4i|^3 ( proven by polar form)=5^3

The answer is b

*Last edited by George,Y (2006-03-16 15:00:58)*

**X'(y-Xβ)=0**

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