Evaluate -(-2)³: Working with Negative Numbers and Exponents

Negative Exponents with Order of Operations

(2)3= -(-2)^3=

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:05 Let's solve the problem together.
00:08 First, let's figure out the sign.
00:11 An odd power means the sign will be negative.
00:20 Now, let's calculate the power of the number.
00:29 Remember, negative times negative gives a positive result.
00:34 And that's how we find the solution to the problem!

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

(2)3= -(-2)^3=

2

Step-by-step solution

To solve the expression (2)3-(-2)^3, we need to first calculate the inner power and then apply the outer negative sign.

  • Step 1: Calculate (2)3(-2)^3.
    Since (2)(-2) is raised to the power of 3, we perform the multiplication: (2)×(2)×(2)(-2) \times (-2) \times (-2).
    (2)×(2)=4(-2) \times (-2) = 4.
    Continuing, 4×(2)=84 \times (-2) = -8.
    Thus, (2)3=8(-2)^3 = -8.
  • Step 2: Apply the outer negative sign.
    We have (2)3=(8)-(-2)^3 = -(-8).
    According to arithmetic rules, a negative times a negative becomes positive, so (8)=8-(-8) = 8.

Therefore, the solution to the problem is 8 8 , which matches choice number 2.

3

Final Answer

8 8

Key Points to Remember

Essential concepts to master this topic
  • Order: Calculate exponent first, then apply outer negative sign
  • Technique: (2)3=(2)×(2)×(2)=8(-2)^3 = (-2) \times (-2) \times (-2) = -8
  • Check: Verify final sign: (8)=+8-(-8) = +8

Common Mistakes

Avoid these frequent errors
  • Applying the negative sign before calculating the exponent
    Don't calculate (2)3-(-2)^3 as (+2)3=8-(+2)^3 = -8! This ignores order of operations and gives the wrong sign. Always calculate the exponent (2)3(-2)^3 first, then apply the outer negative.

Practice Quiz

Test your knowledge with interactive questions

\( (-2)^7= \)

FAQ

Everything you need to know about this question

Why is (-2)³ negative when I'm cubing a number?

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When you cube a negative number, you get a negative result because you multiply an odd number of negative factors: (2)×(2)×(2)=8(-2) \times (-2) \times (-2) = -8. Remember: odd powers of negatives stay negative!

What's the difference between -2³ and (-2)³?

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Big difference! 23=(23)=8-2^3 = -(2^3) = -8 (negative applied after), but (2)3=(2)×(2)×(2)=8(-2)^3 = (-2) \times (-2) \times (-2) = -8 (negative is part of the base). The parentheses matter!

How do I handle the double negative in -(-8)?

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Double negatives become positive! Think of it as "the opposite of negative 8" which equals positive 8. So (8)=+8-(-8) = +8.

What if the exponent was even instead of 3?

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With even exponents, (2)2=4(-2)^2 = 4 (positive), so (2)2=4-(-2)^2 = -4. Even powers of negative numbers are always positive, odd powers stay negative.

Can I just ignore the parentheses around -2?

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Never ignore parentheses! They show that the negative sign is part of the base being raised to the power. Without them, you'd calculate 23=8-2^3 = -8 instead of (2)3=8(-2)^3 = -8.

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