Question 993545
Electronic calculator or table of logarithms.


{{{4*log(10,0.9)=log(10,x)}}}
{{{4(-0.0457575)=log(10,x)}}}
{{{-0.18303=log(10,x)}}}


{{{x=antilog(10,-0.18303)}}}-------this text did not render, so,
{{{x=10^(-0.18303)}}}
{{{highlight(x=0.6561)}}}