write the system of equations represented by the matrix.
{0 1 2 4]
{-2 3 6 9]
{1 0 1 3]

a:
x+2y=4
-2x-3y+69=0
x+y=3

b:
x+2y=4
-2-3y+6=9
x+y=3

c:
y+2z=4
-2x+3y+6z=9
x+z=3

d:
x+2z=4
-2x-3y+6=9