Question 469824
I'm assuming {{{a^2 - am + bm + b^2}}} equals zero? otherwise we can't solve for m
{{{a^2 - am + bm + b^2=0}}}
{{{ m(b-a)=-a^2-b^2}}}
{{{ m(b-a)=(-a^2-b^2)/(b-a)}}}
{{{ m =-(a^2+b^2)/(-(a-b))}}}
{{{ m =(a^2+b^2)/(a-b)}}} 
so the answer is D