Resposta :
Resposta:
[tex]\textsf{Leia abaixo}[/tex]
Explicação passo-a-passo:
[tex]\mathsf{A = A_0.e^{-0.000124t}}[/tex]
[tex]\mathsf{0,20 = 1.e^{-0.000124t}}[/tex]
[tex]\mathsf{0,20 = e^{-0.000124t}}[/tex]
[tex]\mathsf{log\:0,20 = log\:e^{-0.000124t}}[/tex]
[tex]\mathsf{log\:0,20 = (-0,000124t).log\:e}[/tex]
[tex]\mathsf{-0,000124t = \dfrac{log\:0,20}{log\:e}}[/tex]
[tex]\mathsf{t = \dfrac{log\:0,20}{(-0,000124).log\:e}}[/tex]
[tex]\boxed{\boxed{\mathsf{t = 12.979,34}}}\leftarrow\textsf{anos}[/tex]