Chapter 1 - Section 1.2 - Operations with Real Numbers and Simplifying Algebraic Expressions - Exercise Set - Page 29: 158

To determine the sign of a product that involves more than two numbers, simply count the number of negative factors (numbers). If there is an odd number of negative factors, then the product must be negative. If there is an even number of negative factors, then the product must be positive.

To determine the sign of a product that involves more than two numbers, simply count the number of negative factors (numbers). If there is an odd number of negative factors, then the product must be negative. If there is an even number of negative factors, then the product must be positive. Example: (i) $3(-2)(-2)(-4) = -48$ This is negative since there are 3 negative factors. (ii) $3(-2)(-2)(4) = 48$ This is positive since there are 2 negative factors.