Question 1126668
(changing to lower-case variables....)


{{{system(2/a-3/b=-1,5/a-6/b=-1/2)}}}


You can choose to multiply E1 by 2.
{{{system(4/a-6/b=-2,5/a-6/b=-1/2)}}}


Now with this system, subtract E1 from E2.

{{{(5/a-6/b)-(4/a-6/b)=-1/2-(-2)}}}

{{{1/a=1&1/2}}}
{{{highlight(a=2/3)}}}

and you can solve for {{{1/b}}} in any method you want.