Simplify the following into the form $a^b$ab:
$\left(6^7\right)^{-3}$(67)−3
$\left(6^{-5}\right)^4$(6−5)4
Evaluate $\left(5^{-9}\right)^0$(5−9)0.
Evaluate $\left(7^0\right)^{-6}$(70)−6.