A system of equations which intersect everywhere is called dependent. Read pages 277 and 278. Notice the equations and the graph shown at the bottom of page 278. Rewrite both equations using slope-intercept form. Observe that the slopes are equal.
Parallel lines have equal slopes.
Ignore the references to the graphing calculator. Reread example 1. Do exercises 1-7 odd. Reread example 2. Substitution is the mathematical word for replacing a variable with a number or a variable expression.