Question

determine o valor de 8^x-1= 128

Answer 1

${8}^{x - 1} = 128 \\ {2}^{3(x - 1)} = {2}^{7} \\ {2}^{3x - 3} = {2}^{7} \\ 3x - 3 = 7 \\ 3x = 7 + 3 \\ 3x = 10 \\ x = \frac{10}{3}$


Resposta final : x = 10/3