### Home > CAAC > Chapter 4 > Lesson 4.2.4 > Problem 4-99

4-99.

How do the current populations and rates of change relate to *y* = *mx + b*?

The rate of change is the slope.

Highland: *y* = 300*x* + 12,100

Lowville: *y* = −250*x* + 21,000

Be sure to identify what the variable represent.

Use the Equal Values Method.