Odpowiedź:
1)
4x - 5y = 7
-2x + 4y = -8 / * 2
4x - 5y = 7
-4x + 8y = -16
-3y = -9 / : (-3)
y = 3
4x - 5 * 3 = 7
- 4x = 7-15
-4x = -8 / : (-4)
x = 2
{ x = 2
{ y = 3
2)
x+y/4 - 3x - y/2 = -4 / * 4
x-y/2 - x+5y/5 = 5 / * 10
x+y - 6x - 2y = -16 / * 5
5x-5y - 2x + 10y = 50
5x+5y - 30x -10y = -80
5x-5y - 2x + 10y= 50
-28x = -30 / : (-28)
x = -30/28
x = - 1 2/28
