Question 470823
{{{system(expr(-1/9)x-expr(1/3)y=1,
expr(-1/6)x-expr(1/4)y=1)}}}
<pre>
Solve the first equation for x

{{{matrix(5,1,
expr(-1/9)x-expr(1/3)y=1,
"(multiply_through_by_LCD=9)",
-x-3y=9,
   -x=9+3y,
    x=-9-3y)}}}

Substitute in the second equation:

{{{matrix(8,1,
expr(-1/6)x-expr(1/4)y=1,
expr(-1/6)(-9-3x)-expr(1/4)y=1,
"(multiply_through_by_LCD=12)",
-2(-9-3y)-3y=12,
18+6y-3y=12,
18+3y=12,
3y=-6,
y=-2)}}}

Substitute in  {{{x=-9-3y}}}

{{{matrix(4,1,

x = -9-3y,
x=-9-3(-2),
x=-9+6,
x=-3)}}}

Solution (x,y) = (-3,-2) choice a.

Edwin</pre>