Fill in each blank so that the resulting statement is true.An equation that expresses a re...

Fill in each blank so that the resulting statement is true.

An equation that expresses a relationship between two or more variables, such as H = (220 − a) is called a/an _______.The process of finding such equations to describe real-world phenomena is called mathematical_________. Such equations, together with the meaning assigned to the variables, are called mathematical __________.