Exponents with Negative Bases Lesson

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In this section, we explore the topic of exponents with negative bases. When we perform operations with exponents and the base is a positive whole number, things are
fairly straight forward.

4^{3} = 4 • 4 • 4 = 64

We simply have 3 factors of 4

When we start involving negative numbers as the base, we run into some confusion. Let's suppose we see: -5^{2}

Does this problem break down into 2 factors of (-5)? No, it does not and this is where we have to pay close attention. Notice how -5 is not inside of parentheses. This tells us we could really write the problem as:

-5^{2} = -1 • 5^{2} = -1 • 25 = -25

The reason 5 is raised to the 2nd power first is due to the order of operations, exponents have a higher priority level than multiplication. Now let's suppose we saw:

(-5)^{2}

This problem is telling us that we have 2 factors of (-5), the difference is that (-5) is enclosed in parentheses, so both the negative and the 5 are raised to the 2nd power:

(-5)^{2} = (-5)(-5) = 25

This shows us we must pay close attention to the details when working with exponents with negative bases. When the base does not have parentheses, we approach the problem differently.

Example 1: (-3)^{4}

(-3)^{4} = (-3)(-3)(-3)(-3) = 81

Example 2: -7^{2}

-7^{2} = -1 • 7^{2} = -1 • 49 = -49

4

We simply have 3 factors of 4

When we start involving negative numbers as the base, we run into some confusion. Let's suppose we see: -5

Does this problem break down into 2 factors of (-5)? No, it does not and this is where we have to pay close attention. Notice how -5 is not inside of parentheses. This tells us we could really write the problem as:

-5

The reason 5 is raised to the 2nd power first is due to the order of operations, exponents have a higher priority level than multiplication. Now let's suppose we saw:

(-5)

This problem is telling us that we have 2 factors of (-5), the difference is that (-5) is enclosed in parentheses, so both the negative and the 5 are raised to the 2nd power:

(-5)

This shows us we must pay close attention to the details when working with exponents with negative bases. When the base does not have parentheses, we approach the problem differently.

Example 1: (-3)

(-3)

Example 2: -7

-7

Exponents with Negative Bases Resources:

Videos:

Khan Academy - Video
Study - Video
Krista King - YouTube - Video
Text Lessons:

Sangakoo - Text Lesson
Cool Math - Text Lesson
Purple Math - Text Lesson
Worksheets:

Karen Mcnabbs - Worksheet
Kid Smart Education - Worksheet
Khan Academy - Practice
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