application or intradermal injection of a substance to the skin to test the body's reaction to it. Such a test detects an animal's sensitivity to such allergens as dust and pollen, or to preparations of microorganisms believed to be the cause of a disorder.
A direct relationship graph is a graph where one variable either increases or decreases along with the other. The general equation for a direct relationship graph is y = mx + b, where y denotes the...
Linear equations like y = 2x + 7 are called linear because they make a straight line when we graph them. These tutorials introduce you to linear relationships, their graphs, and functions. When you walk at a constant rate, the relationship between the distance you've walked and the time you've spent walking is proportional. In this tutorial, we learn about proportional relationships (constant rates) and their graphs..