Introduction

Refer to the following figure:

You learned in the previous grades that angles with measures of 30° and 60° are complementary since ${30}^{\circ }+{60}^{\circ }={90}^{\circ }.$ In general, any two angles whose measures have a sum of 90° are complementary. Among all possible pairs of complementary angles, which pair will give a difference of 26°?

The problem stated in the paragraph above can be translated into a system of two linear equations in two variables. In this section, you will learn about this kind of linear equations. In particular, you will study the solution of a system of two linear equations in two variables and its classification.