Exercise 26 Page 210

We want to know how many of the songs the DJ has in her system are dance, rock, and country. Let's create a system of linear equations and then solve it using the Substitution Method. We will do these things one at a time, starting with forming a system. We will use $x$ for the number of dance songs, $y$ for the rock songs, and $z$ for the country songs. From the exercise, we know that there are $1075$ songs in total in the system. That means that the sum of all three different song types is $1075.$ Let's write this fact as an equation.