The use of the insecticide DDT was banned in the United States in 1972. A computer analysis shows that an expression relating the amount A still present in an area, the original amount A , 0 and the time t (in years) since 1972 is log₁₀ A = log₁₀ A₀ + 0.1t log₁₀ 0.8. Solve for A as a function of t.