SOLUTION: Use the given information about the polynomial graph to write the equation. Degree 5. Roots of multiplicity 2 at x = −3 and x = 2 and a root of multiplicity 1 at x = −

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Use the given information about the polynomial graph to write the equation. Degree 5. Roots of multiplicity 2 at x = −3 and x = 2 and a root of multiplicity 1 at x = −      Log On


   



Question 1127668: Use the given information about the polynomial graph to write the equation.
Degree 5. Roots of multiplicity 2 at x = −3 and x = 2 and a root of multiplicity 1 at x = −2. y-intercept at (x, y) = (0, 44).
*somewhere I keep going wrong because the answers that I’ve gotten so far are incorrect:
1 63/100 (x+3)^2 (x+2) (x-2)^2,
18/11 (x+3)^2 (x+2) (x-2)^2,
1 7/11(x+3)^2 (x+2) (x-2)^2.

Found 2 solutions by MathLover1, greenestamps:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
given:
Degree 5
Roots of multiplicity 2 at+x+=+-3 and x+=+2 and a root of multiplicity 1 at x+=+-2.
y-intercept at (x, y) = (0, 44).

f%28x%29=a%28%28x%2B3%29%5E2+%28x%2B2%29+%28x-2%29%5E2%29
f%28x%29=a%28x%5E5+%2B+4+x%5E4+-+7+x%5E3+-+34+x%5E2+%2B+12+x+%2B+72%29

given: f%280%29=44
44=a%280%5E5+%2B+4+%2A0%5E4+-+7+%2A0%5E3+-+34+%2A0%5E2+%2B+12+%2A0+%2B+72%29
44=72a
a=11%2F18
f%28x%29=%2811%2F18%29%28x%5E5+%2B+4+x%5E4+-+7+x%5E3+-+34+x%5E2+%2B+12+x+%2B+72%29



Answer by greenestamps(13209) About Me  (Show Source):
You can put this solution on YOUR website!


First, regarding what you show that is (I think) the answers you have gotten so far.

(1) Never write the coefficient of a polynomial as a mixed number. "1 7/11(x+3)^2 (x+2) (x-2)^2" is very bad form.
(2) The answer with 18/11 is close; it should be 11/18. Perhaps you made a simple algebra error and ended up with an answer that is the reciprocal of the right answer.

Now, regarding how to find that coefficient....

It appears you don't need to write the answer in expanded form; so I wouldn't go to all the work that the other tutor showed.

You know from the given roots that the polynomial is of the form

a%28%28x%2B3%29%5E2%28x%2B2%29%28x-2%29%5E2%29

The only task is to find the value of a.

To do that, use the fact that f(0) = 44:

a%283%5E2%29%282%29%28-2%29%5E2+=+44
a%289%29%282%29%284%29+=+44
72a+=+44
a+=+44%2F72+=+11%2F18

The polynomial in factored form is

p%28x%29+=+%2811%2F18%29%28%28x%2B3%29%5E2%28x%2B2%29%28x-2%29%5E2%29