NSolve[0 == 1.33 - (0.059/6)* Log10[((X/60)^2)/(((25 - 7*X + 10^(-7))/60)^14*0.5*X)] - (-0.43 - 0.0295*Log10[1/((25 + 5.9 - 1.5*X)/60)]), X, Reals, WorkingPrecision -> 30]