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The polynomial of degree 5,

P(x) has leading coefficient 1, has roots of multiplicity 2 at x = 1 and x = 0, and a root of multiplicity 1 at
x = -5 Find a possible formula for P(x).

User Nixda
by
7.7k points

2 Answers

3 votes

Answer:

Step-by-step explanation:

Given the information that the polynomial function P(x) has leading coefficient 1, has roots of multiplicity 2 at x = 1 and x = 0, and a root of multiplicity 1 at x = -5, we can use this information to find a possible formula for P(x).

A polynomial function's roots are the values of x that make the function equal to zero. If a root has multiplicity n, it means that (x - root) is a factor of the polynomial function n times.

So, based on the given information, we know that P(x) must be divisible by the factors (x - 1)^2, (x - 0)^2, and (x + 5), and that the leading coefficient must be 1.

Putting it all together, a possible formula for P(x) is:

P(x) = (x - 1)^2 (x - 0)^2 (x + 5) = (x^2 - 2x + 1)(x^2)(x + 5) = x^6 - 7x^5 + 17x^4 - 22x^3 + 17x^2 - 7x + 5

So, the possible formula for P(x) is P(x) = x^6 - 7x^5 + 17x^4 - 22x^3 + 17x^2 - 7x + 5.

User Gabor De Mooij
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6.3k points
3 votes

Answer:
P(\text{x}) = \text{x}^2(\text{x}-1)^2(\text{x}+5)

Step-by-step explanation:

If k is a root of P(x), then x-k is a factor. The multiplicity is the exponent for that factor.

For instance, the root x = 1 with multiplicity 2 leads to the factor
(\text{x}-1)^2

The leading coefficient is the number out front. For example, if the leading coefficient was 8, then we'd have
P(\text{x}) =8\text{x}^2(\text{x}-1)^2(\text{x}+5)

However, we change that "8" to a "1" since the leading coefficient is 1 here.

That's how we get to


P(\text{x}) = 1\text{x}^2(\text{x}-1)^2(\text{x}+5) aka
P(\text{x}) = \text{x}^2(\text{x}-1)^2(\text{x}+5)

Optionally if you were to expand everything out, combine like terms, and simplify then you'd get


P(\text{x}) = \text{x}^2(\text{x}-1)^2(\text{x}+5) = \text{x}^5 + 3\text{x}^4- 9\text{x}^3+5\text{x}^2

I don't recommend doing this because you lose the information about the roots along with their corresponding multiplicities. It's better to keep things factored.

You can use a graphing tool like Desmos or GeoGebra to verify the answer.

User Andrey Solera
by
7.5k points