6)
multiply 2nd equation by -3
-3x + 15y = -51
3x + 2y = 0
---------------------------add
17y = -51
y = -3
3x + 2y = 0
3x + 2(-3) = 0
3x = 6
x = 2
answer (2 , -3)
7)
multiply 2nd equation by -2
-2x -4y = -10
2x + 3y = 6
-------------------add
-y = -4
y = 4
2x + 3y = 6
2x + 3(4) = 6
2x + 12 = 6
2x = -6
x = -3
answer (-3, 4)
8)
multiply 1st equation by 2
6x -2y = 4
x + 2y =3
---------------add
7x = 7
x = 1
x + 2y =3
1 + 2y =3
2y = 2
y = 1
answer (1,1)
9)
multiply 1st equation by 3 : 12x + 15y = 18
multiply 2nd equation by -2: -12x + 14y = 40
------------------------add
29y = 58
y = 2
4x + 5y = 6
4x +5(2) = 6
4x + 10 = 6
4x = -4
x = -1
answer (-1,2)
10)
multiply 2nd equation by 2
32x - 2y = 28
4x + 2y = 8
----------------add
36x = 36
x = 1
4x + 2y = 8
4(1) + 2y = 8
2y = 4
y = 2
answer (1,2)
