Math Qs HELP PLEASE !

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1

<p>*If f(x) = x^4 - 3x^3 - 9x^2 + 4, for how many
real numbers of k does f(k) = 2 ?
(A) None (B) One (C) Two (D) Three (E) Four</p>

<p>time (t) : 0------ 1 ------- 2 -------- 5
value v(t): 15000 --13000 --10900 -- 3000 </p>

<p>*When purchased, an automobile is valued at
$15,000. Its value depreciates at the rate
shown in the table above. Based on a least squares
linear regression, what is the value,
to the nearest hundred dollars, of the
automobile when t=4 ?
(A) $5,400 (B) $5,500 (C) $5,600 (D) $6,400 (E) $7,000</p>

<p>i would really appreciate your input
thanks</p>

2

<p>c'mon ppl time wont wait i really need your help !
bump</p>

3

<p>Second answer....
When bought, the value of the car is 15K
1 year later, its value decreased by 2k. So, its value after 1 year is 15K-2K=13K
After 1 more year, its value decreases to 10.9K. That means, its value decreases by 2.1K
So the decrease in value is an AP. Following this AP, price at the end of 3 years is 10.9K-2.2K=8.7K
The value of the car at the end of 4 years will be 8.7K-2.3K=6.4K
The value of the car at t=4 is 6400
Hope this helps</p>

4

<p>aha ic but whats AP?</p>

5

<p>Arithmetic Progression...A term exceeds the previous by a definite amount...In this case, 0.1K
So, after 1, 2, 3 and 4 years, Value of car decreases by 2.0k, 2.1k, 2.2k, and 2.4K respectively</p>

6

<p>*If f(x) = x^4 - 3x^3 - 9x^2 + 4, for how many
real numbers of k does f(k) = 2 ?
(A) None (B) One (C) Two (D) Three (E) Four</p>

<p>This one is supereasy but you have to read what its asking you.</p>

<p>so putting k into the equation:</p>

<p>k^4-3k^3-9k^2+4=2</p>

<p>so thats</p>

<p>k^4-3k^3-9k^2+2=0</p>

<p>Solve using "polysmlt" application on ti-83, and you get 2 real and 2 non-real answers, so B is your answer.</p>

<p>Cheers.</p>