Algebra 1 A group of scientists studied the effect of a chemical on various strains
of bacteria. Strain A started with 9000 cells and decreased at a constant rate of 3000 cells per hour after the chemical was applied. Strain B started with 4000 cells and decreased at a constant rate of 2000 cells per hour after the chemical was applied. When will the strains have the same number of cells? Explain.

To determine when the strains will have the same number of cells, first write and solve a system of two linear equations.

The solution to the system of linear equations is .