Question

Вычислите: 7^-7*7^-8/7^-13

Answer 1

$\frac{7^{-7}*7^{-8}}{7^{-13}}=\frac{7^{-7-8}}{7^{-13}}=\frac{7^{-15}}{7{-13}}=7^{-15-(-13)}=7^{-2}=\frac{1}{49}$

Answer 2

$\frac{7 {}^{ - 7} \times {7}^{ - 8} }{ {7}^{ - 13} } = \frac{7 {}^{ - 7 - 8} }{ {7}^{ - 13} } = \frac{ {7}^{ - 15} }{7 {}^{ - 13} } = 7 {}^{ - 15 - ( - 13)} = 7 - {}^{ - 15 + 13} = {7}^{ - 2} = \frac{1}{ {7}^{2} } = \frac{1}{49}$