Solve the exponential equation. 1/16 = 64x a. -2/3 b. 2/3 c. 3/2

We have that
1/16 = 64^x
applying log both sides
log(1/16)=log(64^x)
log 1-log16=x*log64
-log 16=x*log 64
divide by log 64 both sides
x=-log 16/log 64
log 16=log 2^4> 4*log 2
log 64=log 2^6> 6*log 2
-log 16/log 64=(-4*log 2)/(6*log 2)> -4/6> -2/3

the answer is 
x=-2/3

1. 8 or -82. 14 or -143. -11, -3, 0, 7, 10

The year before the 10s so it was like when caveman were alive