Question 1009183
The a  and b  are  {{{(10+- sqrt(100-4*7))/2}}},
{{{(100+- sqrt(72))/2}}}
{{{(100+- sqrt(2*36))/2}}}
{{{(100+- 6sqrt(2))/2}}}


{{{highlight_green(50+- 3sqrt(2))}}}



Unfinished.  Question now asks for {{{a^4-b^4}}}.
You might want to try  (a^2-b^2)(a^2+b^2).