Question 469442
{{{log(2, 7x) + log(2, x) = 3}}}, {{{x>0}}}
Use formula {{{log(c,a)+log(c,b)=log(c,(a*b))}}}
{{{log(2, (7x*x)) = 3}}}
{{{log(2, (7x^2)) = 3}}}
Use formula {{{log(c,a)=b}}}<=>{{{a=c^b}}}
{{{7x^2=2^3}}}
{{{7x^2=8}}}
{{{x^2=8/7}}}
{{{x=sqrt(8/7)=1.069}}}
{{{x=-sqrt(8/7)<0}}}extraneous root
Answer {{{x=sqrt(8/7)=1.069}}}