Final answer:
The correct equation for the product of a number and -5 being less than 30 is -5x < 30, which depicts an inequality with a boundary line that would have a negative slope if graphed.
Step-by-step explanation:
The equation representing the relationship "the product of a number and -5 is less than 30" can be written as -5x < 30. This indicates that when you multiply a number x by -5, the result should be less than 30. The correct answer is (c) -5x < 30. Since this is an inequality, if we were to graph this on a coordinate plane, it would represent a region and not a line. However, the boundary of this region, if equality were considered, would be a straight line with a negative slope.