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Write a polynomial P(x), in factored form given the following requirements

• Degree: 3
• Leading coeffcient: 1
• x-intercepts at (10,0) and (−1,0)
• y-intercept at (0,−40)

User Saluce
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1 Answer

3 votes

Answer:

The polynomial in factored form is:

P(x) = (x-10)(x+1)(x+1)

or, we can write it in expanded form as:

P(x) = x^3 - 8x^2 - 11x + 40.

Explanation:

If the x-intercepts are at (10,0) and (-1,0), then the polynomial must have factors of (x-10) and (x+1). If the y-intercept is at (0,-40), then the constant term must be -40.

To satisfy the given requirements, we can write the polynomial as:

P(x) = (x-10)(x+1)(x-a)

where a is a constant that we need to determine. To find a, we can use the fact that the leading coefficient is 1.

Expanding the expression above, we get:

P(x) = (x^2 - 9x - 10)(x-a)

= x^3 - ax^2 - 9x^2 + 9ax - 10x + 10a

= x^3 - (a+9)x^2 + (9a-10)x + 10a

Since the leading coefficient is 1, we know that the coefficient of x^3 is 1. Therefore, we must have:

1 = 1*(-a-9)*(9a-10)

Simplifying and solving for a, we get:

a = -1

Therefore, the polynomial in factored form is:

P(x) = (x-10)(x+1)(x+1)

or, we can write it in expanded form as:

P(x) = x^3 - 8x^2 - 11x + 40.

User Bryanna
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