Metoda przeciwnych współczynników
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4x - 3y = 3
x - 3y = -6 /× -1
4x - 3y = 3
- x + 3y = 6
3x = 9 /: 3
x = 3
4x - 3y = 3
- 3y = 3 - 12
- 3y = -9 /× -1
3y = 9 /:3
y = 3
4× 3 - 3 x 3 = 12 - 9 = 3
3 - (-3×3)= 3 - 9 = -6