Question 50658
This is assumed to be log base 10, so it can be written as 
{{{log (10, 98-x+x^2) = 2}}}
This means that {{{10^2 = 98-x+x^2}}}
{{{100=98-x+x^2}}}


Set equal to zero by subtracting 100 from each side:
{{{100-100=98-100-x+x^2}}}
{{{0 = x^2 -x -2}}}
{{{0= (x-2)(x+1)}}}
{{{x=2}}} or {{{x=-1}}}


You must reject x = -1, since you cannot have a log of a negative!!
Final answer is x = 2.  By the way it checks:
{{{log(10, (98-2+4)) = log(10, 100) = 2}}}


R^2 at SCC