SOLUTION: I really need help with this problem. Please show every step by step. Thank you The polynomial of degree 4, P(x)  has a root of multiplicity 2 at x=2  and roots of multiplicit

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I really need help with this problem. Please show every step by step. Thank you The polynomial of degree 4, P(x)  has a root of multiplicity 2 at x=2  and roots of multiplicit      Log On


   



Question 995119: I really need help with this problem. Please show every step by step. Thank you

The polynomial of degree 4, P(x)  has a root of multiplicity 2 at x=2  and roots of multiplicity 1 at x=0  and x=−2  . It goes through the point (5,252)  .
Find a formula for P(x)  .

Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
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The polynomial of degree 4, P(x) has a root of multiplicity 2 at x=2 and roots of multiplicity 1 at x=0 and x=−2. It goes through the point (5,252).
Find a formula for P(x).
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According to the given information about the roots,  the polynomial is

P(x) =  a%2A%28x-2%29%5E2%2A%28x-0%29%2A%28x-%28-2%29%29 = a%2A%28x-2%29%5E2%2Ax%2A%28x%2B2%29           (1)

with some unknown real coefficient  a.

To find  a,  use the fact that the plot of the polynomial goes through the point  (5,252).  It means that  P(5) = 252.
So,  simply substitute  x=5  into the polynomial  (1). You will get the equation

a%2A%285-2%29%5E2%2A5%2A%285%2B2%29 = 252,     or

a%2A3%5E2%2A5%2A7 = 252,       or

315a = 252.

Hence,  a = 252%2F315 = 4%2F5.

Therefore,  P(x) = 4%2F5.%28x-2%29%5E2%2Ax%2A%28x%2B2%29.

You can open the parentheses if you need.