Precalculus : Pre-Calculus

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #1 : Understanding Zeros Of A Polynomial

Factor the polynomial if the expression is equal to zero when .

Possible Answers:

Correct answer:

Explanation:

Knowing the zeroes makes it relatively easy to factor the polynomial.

The expression fits the description of the zeroes.

Now we need to check the answer.

We are able to get back to the original expression, meaning that the answer is .

Example Question #2 : Understanding Zeros Of A Polynomial

A polyomial with leading term  has 6 as a triple root. What is this polynomial?

Possible Answers:

 

Correct answer:

Explanation:

Since 6 is a triple root, and the degree of the polynomial is 3, the polynomial is , which we can expland using the cube of a binomial pattern.

Example Question #91 : Pre Calculus

What is the highest multiplicity of the zeros in the polynomial 

Possible Answers:

None of the other answers

Correct answer:

Explanation:

In the form given we can readily see that the polynomial has three zeros .  We observe that the zero at  has multiplicity of two whereas the others both have a multiplicity of one.  This make our answer .

Example Question #92 : Pre Calculus

Find the zeros of the given polynomial. 

Possible Answers:

Correct answer:

Explanation:

The zeros of the polynomial are the values of  that set it equal to zero. In the given form we can clearly see that whenever any of the portions grouped in parentheses is equal to zero then the whole polynomial will be equal to zero. Since anything multiplied by zero is equal to zero. This fact lead us to our answer.

Example Question #15 : Polynomial Functions

Find the zeros of following polynomial:

 

Possible Answers:

Correct answer:

Explanation:

To find the zeros we need to factor this polynomial. We start by grouping the terms and pulling out a common factor.

 

now our two groups have a common factor so we pull that out and we get 

 

this can be factored further into 

and then we see that the x values that make each one of those terms 0 respectively are 

 

 

Example Question #95 : Pre Calculus

Zeros of a cubic.

Find the zeros of the function

.

Possible Answers:

.

.

.

.

Correct answer:

.

Explanation:

This is a 3rd order polynomial that can be factored.  The leading coefficient is 1, so only the second term in each factor need be considered.

, and so f factors into

.

At this point the shortcut

can be used.

Now the final factorization is

.

The zeros occur when each of the factors is zero, so

,

, and

.

Example Question #93 : Pre Calculus

A polynomial with the leading term has 2 as a triple root. What is the polynomial?

Possible Answers:

Correct answer:

Explanation:

For a polynomial to have 2 as a triple root, 2 must be it's solution 3 times. Solving this backwards, we start by constucting the final equation and working backwards.

The above equation gives us 2 as a triple root, so the polynomial on the left is what we are looking for.

Example Question #97 : Pre Calculus

Zeros of a quadratic.

Find the roots of

.

Possible Answers:

.

.

Correct answer:

.

Explanation:

Set y=0, then factor.  The leading coefficient is 12, so its factors need to be considered.  Trial and error will lead to 3 and 4 as the best choice combined with using 2 and -2 to give the last term.

Thus .

y=0 when either of the factors are 0.

So,

,

and

.

Example Question #94 : Pre Calculus

Find the zeros of the following polynomial:

Possible Answers:

Correct answer:

Explanation:

To find the zeros of a polynomial, we have set it equal to 0, factor it, and solve for x.

Example Question #95 : Pre Calculus

Find the zeros of the following polynomials.

Possible Answers:

Correct answer:

Explanation:

To find the zeros, we must set the polynomial equal to 0, factor, and solve.

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