The bacteria Streptococcus lactis doubles every 26 minutes in milk. If a container of milk contains 4 bacteria, write an equation that models this scenario and then graph the equation.

Read the problem statement and then reread the scenario, identifying the known quantities.

Substitute the known quantities into the general form of the exponential equation , for which is the initial value, is the base, is time (in this case, 1 time period is 26 minutes), and is the final value.

Create a table of values.

Set up the coordinate plane.

Plot the points on the coordinate plane and connect the points with a line (curve). When the points do not lie on a grid line, use estimation to approximate where the point should be plotted. Add an arrow to the right end of the line to show that the curve continues in that direction toward infinity.

This applet is provided by Walch Education as supplemental material for the CCGPS Coordinate Algebra program. Visit www.walch.com for more information on our resources.