Question 830186
{{{(matrix(2,3,-7,-2x,1,9y,-1,0))+3*(matrix(2,3,12,9,0,10,-1,2))=(matrix(2,3,29,5x^2,13,-4y,-4,6))}}}

{{{(matrix(2,3,-7,-2x,1,9y,-1,0))+(matrix(2,3,36,27,0,30,-3,6))=(matrix(2,3,29,5x^2,13,-4y,-4,6))}}}

Then check element by element.
1.{{{-7+36=29}}}
2.{{{-2x+27=5x^2}}}
3.{{{1+0=13}}}
4.{{{9y+30=-4y}}}
5.{{{-1-3=-4}}}
6.{{{0+6=6}}}
From 2,
{{{-2x+27=5x^2}}}
{{{5x^2+2x-27=0}}}
Use the quadratic formula to solve for {{{x}}}
From 4,
{{{9y+30=-4y}}}
{{{13y=-30}}}
{{{y=-30/13}}}
However 3 does not make sense since, 1+0 does not equal 13.