volume_mute
Even vs. Odd Number of Negative Factors
publish date: 2026/05/07 07:22:12.019957 UTC
volume_mute
Select all expressions whose product is positive based on the rule about the number of negative factors.
Correct Answer
(1) \((-3)^{20}\)
(2) \((-2)(-4)(-6)(-8)\)
Explanation
Count the negative factors:
- \((-5)^{13}\): 13 negatives → odd → negative
- \((-3)^{20}\): 20 negatives → even → positive ✓
- \((-2)(-4)(-6)(-8)\): 4 negatives → even → positive ✓
- \((-1)(-2)(-3)(-4)(-5)\): 5 negatives → odd → negative
Reference
Mathematics for college students