Algebra II : Basic Operations with Complex Numbers

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #21 : Basic Operations With Complex Numbers

Simplify:

Possible Answers:

Correct answer:

Explanation:

Use FOIL to multiply the binomials:

Change  to -1:

Combine like terms:

Example Question #22 : Basic Operations With Complex Numbers

Find

Possible Answers:

Correct answer:

Explanation:

This pattern repeats every four powers. Divide the power by 4:

Since the remainder is 3, it is equivalent to , or .

Example Question #81 : Imaginary Numbers

Simplify the following:

Possible Answers:

Correct answer:

Explanation:

To solve this type of problem, it is easiest to divide the exponent by 4 and see what the remainder is. The reason we choose 4 is because , so   - where x is the number of times can go into our exponent - will equal 1 as well.

So,

 

Example Question #21 : Basic Operations With Complex Numbers

Simplify the following expression:

Possible Answers:

Correct answer:

Explanation:

To simplify the given expression, we can FOIL the two binomials, to get

which can be simplified to

given that  and  is in its simplest form.

Example Question #21 : Number Theory

Simplify:

Possible Answers:

Correct answer:

Explanation:

First remember the form of the complex number:

Where "a" is the "Real" part, and "b" is the imaginary part.

Only the real parts can be combined together, and only the imaginary parts can be combined together.

Therefore the equation becomes after distributing the negative sign:

Collect the real and imaginary terms together:

Giving the answer:

Example Question #83 : Imaginary Numbers

Simplify:

Possible Answers:

Correct answer:

Explanation:

To simplify the expression, we must keep in mind the following:

Now, we can use FOIL to simplify the product of the two binomials:

Next, simplify and combine like terms:

Example Question #22 : Basic Operations With Complex Numbers

Multiply:

Possible Answers:

Correct answer:

Explanation:

To multiply this expression, use the distributive property:

.

Recall that

so

.

Therefore, your answer is

.

Example Question #27 : Basic Operations With Complex Numbers

Simplify:

Possible Answers:

Correct answer:

Explanation:

To simplify, we can start by remembering the following:

Now, rewrite the first term with the above in mind:

Finally, FOIL the complex numbers:

Example Question #28 : Basic Operations With Complex Numbers

Simplify:  

Possible Answers:

Correct answer:

Explanation:

Multiply the conjugate of the denominator.

Solve the numerator.  Remember that  and .

Solve the denominator.  Simplify the terms with the .

Multiply these two terms together.

Divide the numerator with the denominator.

The answer is:  

Example Question #29 : Basic Operations With Complex Numbers

Simplify:  

Possible Answers:

Correct answer:

Explanation:

In order to simplify this expression, pull out a common factor of  out of the numerator and denominator.  There is no need to multiply both the numerator and denominator by the conjugate of the denominator.

Recall that since , the value of .

Replace that term in numerator.

The expression becomes:

This expression is equal to .

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