Question 737110
What base?  Assuming base 10, or any  base, {{{log(10, 10)=1}}}, because {{{10^1=10}}}.  


Assuming any base, b:
{{{1-2*log(b,7x)=log(b,b)-2*log(b,7x)}}}
={{{log(b,b)-log(b,(7x)^2)}}}
={{{highlight(log(b,((b)/(7x)^2)))}}}