Question 1009256
{{{4x+7y=28}}}...solve for {{{y}}}

move {{{4x}}} to the right; you can add {{{-4x}}} to both sides and it will eliminate {{{4x}}} on left side
 
{{{4x-4x+7y=-4x+28}}}

{{{cross(4x)-cross(4x)+7y=-4x+28}}}

{{{7y=-4x+28}}}............both sides divide by {{{7}}} to single out {{{y}}}

{{{7y/7=-4x/7+28/7}}}

{{{y=-(4/7)x+4}}}