given,
3x+2y=10, 2x-y=9
3x+2y=10
or, 3x=10-2y
or, x=(10-2y)/3
substituting value of x, we get
2(10/3-2y/3)-y=9
or, (20-4y)/3-y=9
or, (20-4y-3y)/3=9
or, (20-7y)/3=9
or,20-7y=27
or, -7=7y
or, y=-1
again,
2x-y=9
or, 2x+1=9
or, 2x=8
or, x=4
therefore, x=4
y=-1