Question 878242
Simplify that to {{{3x+y=4}}}.
Keeping the same slope to make for parallel line, use ANY value you want for the constant term, call it k.  3x+y=k for any real constant value; and solve this for y:


{{{highlight(y=-3x+k)}}} for any {{{k<>12}}}, parallel to {{{9x+3y=12}}}.