Answers270311 - UCLA - Algebra 2 semester 1The Fundamental Theorem of Algebra

Writing Polynomial Functions from Complex Roots Answers

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What are the zeroes of the function?

A
–3
B
–2
C
2
D
3
E
5
3

To solve for the leading coefficient, use a = –5(0 – 2)(0 – 3)(0 – 5) a = 5(0 – 2)(0 – 3)(0 – 5) 5 = a(0 – 2)(0 – 3)(0 – 5)✔ –5 = a(0 – 2)(0 – 3)(0 – 5).

A
a = –5(0 – 2)(0 – 3)(0 – 5)
B
a = 5(0 – 2)(0 – 3)(0 – 5)
C
5 = a(0 – 2)(0 – 3)(0 – 5)
D
✔ –5 = a(0 – 2)(0 – 3)(0 – 5)
11

The linear factors of the cubic are ✔ (x – 2)(x – 3)(x – 5)(x – 2)(x – 3)(x – 5)(x + 5)(x + 2)(x + 3)(x + 5)(x + 2)(x + 3)(x – 5).

A
✔ (x – 2)(x – 3)(x – 5)
B
(x – 2)(x – 3)(x – 5)(x + 5)
C
(x + 2)(x + 3)(x + 5)
D
(x + 2)(x + 3)(x – 5)
13

The equation of the polynomial function is:

A
f(x) = (x + (2 + i))(x + (2 – i))(x + 5)
B
f(x) = (x – (2 + i))(x – (2 – i))(x – 5)
C
f(x) = (x – (2 + i))(x – (2 – i))
D
f(x) = (x + (2 + i))(x – (2 – i))(x – 5)
14

f(x) = x4 − [___]x3 + [___]x2 + [___]x − [___]

Question illustration
Answers:
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15

f(x) = x3 − [___]x2 + [___]x − [___]

Answers:
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19

Write an equation for the cubic polynomial function whose graph has zeroes at 2, 3, and 5. [image 1] Can any of the roots have multiplicity? [image 2] How can you find a function that has these roots?

Question illustration
Answer:

One such function is f(x) = (x − 2)(x − 3)(x − 5) = x³ − 10x² + 31x − 30. None of the roots can have multiplicity greater than 1 because the three distinct roots already account for the cubic’s degree. Write each root as a linear factor and multiply the factors.

20

Which of the following did you include in your explanation?

A
The roots cannot have multiplicity because the function is specified as cubic and 3 roots are given.
B
To find the function, write f(x) = (x – 2)(x – 3)(x – 5), and simplify the right side.

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