Question 925162
Solve for x in terms of k.
log_(7) x + log_(7) (x+10) = k. 
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{{{log(7,(x))+log(7,(x+10))=k}}}
{{{log(7,((x)(x+10)))=k}}}
base(7)raised to log of number(k)=number(x(x+10))
7^k=x(x+10)=x^2+10x
x^2+10x-7^k=0
solve for x by quadratic formula:
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
a=1, b=10, c=7^k
{{{x = (-10 +- sqrt( 100-4*1*7^k ))/(2) }}}
{{{x = (-10 +- sqrt( 100-4*7^k ))/(2) }}}