[tex]b) \: \frac{1}{7} = \frac{1}{343} [/tex]
[tex] {7}^{ - n} = {7}^{ - 3} [/tex]
[tex] - n = - 3[/tex]
[tex]n = 3[/tex]
[tex]d) \: (2 \times \frac{1}{2} ) ^{n} = \frac{125}{8} [/tex]
[tex]2 \times \frac{1}{2} = \frac{2 \times 2 + 1}{2} = \frac{5}{2} [/tex]
(5supra2)^n=125supra8
(5supra2)^n=(5supra2)^3
n=3
