i do not know how to solve this

Question

8^-x=15. what is x ? and what will x be for 8^2x=?

Answer 1

First 8^-x is 1/8^x so 1/8^x=15

1/15=8^x Now take the log of both sides

ln(1/15)= ln8^x

remember the log property loga^x =xloga so

ln(1/15)=xln8

x=ln(1/15)/ln8

x=-1.3

8^2x = 8^-2.6= 1/8^2.6= ~1/223

Answer 2

8^-x = 15

-x ln 8 = ln 15

-2.079x ≈ 2.798

x ≈ -1.302

8²x = 64x