Y-4X =3 ; 2x-3y=21
Y= 3+ 4x
2x -3( 3+4x)= 21
2x- 9- 12x= 21
-10x -9= 21
-10x -9+9= 21+9
-10x = 30
X= 30/-10= -3
Y= 3+4x = 3+ 4* (-3)= 3-12= -9
