Question

What is the solution of −81=b6 ? A. b = −486 B. b = −75 C. b = 13.5 D. b = 486

Answer 1

We have to isolate b to be alone. 
Soooo first we divide both sides by 6

-81 = b6
÷6  = ÷6  The right side cancels out and gets the b alone. While we solve the right side of the equal sign. 
-81 ÷ 6 = -13.5 
So this means we isolated b alone!
b = -13.5 

Our final answer is..
b = -13.5 

:)