Multiplying two integers that have different signs gives a product that is:

1. A product changes sign when only one factor is negative. 2. The sign of the product depends on the signs of the two numbers. 3. Multiplying two integers with different signs results in a negative product. 4. So the product comes out negative. _Source: OpenStax Prealgebra 2e (CC BY 4.0), Ch 3 'Integers', sections 3.1-3.5_