Question

A) 3×-y=0
-4×+y=-2

B) 4×6y=-12
-2×+3y=6

C) -6×+2y=8
9×-y=8

D) 2×-y=10
4×+2y=20

Answer 1

A)
  3x - y = 0
- 4x + y = - 2  (+)
----------------------
  - x = - 2  (-1)
    x = 2

3x - y = 0
3x = y
y = 3x
y = 3.2
y = 6

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B)
  4x + 6y = - 12   (:2)
- 2x + 3y = 6

  2x + 3y = - 6
- 2x + 3y = 6 (+)
------------------------
        6y = 0
         y = 0/6
         y = 0

2x + 3y = - 6
2x + 3.0 = - 6
2x = - 6
x = - 6/2
x = - 3

C)
- 6x + 2y = 8
  9x - y = 8      (2)

- 6x + 2y = 8
18x - 2y = 16  (+)
-------------------------
12x = 24
x = 24/12
x = 2

9x - y = 8
9.2 - y = 8
18 - y = 8
18 - 8 = y
10 = y
y = 10

D)
2x - y = 10
4x + 2y = 20  (:2)

2x - y = 10
2x + y = 10 (+)
-----------------------
4x = 20
x = 20/4
x = 5

2x - y = 10
2.5 - y = 10
10 - y = 10
10 - 10 = y
0 = y
y = 0