四題指數定律

1. 2^-7 x 4^-3 ÷8^-6
= 2^-7 x 2^-6 x 8^6
= 2^-13 x [(2)^3]^6
= 2^-13 x 2^18
= 2^5
= 32


2.5^3 x 15^-2 ÷(-5^-2)
= 5^3 x 15^-2 x (-5^2)
= -5^5 x (5 x 3)^-2
= -5^5 x 5^-2 x 3^-2
= -5^3 x 3^-2
= -125/9


3.7^2 - 7^-13 ÷ 7^-14
= 7^2 - 7^-13 x 7^14
= 7^2 - 7
= 7x(7-1)
= 42


5. (-4a^-1 b^-1)^-1
= (-4)^-1 (a^-1)^-1 (b^-1)^-1
= (-4)^-1 a b
= ab/(-4)
= -ab/4