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2010-01-23T17:54:30+01:00
C)
2x-3y=-5
-x+5y=6

2x-3y=-5
x = - 6 + 5y

2 * (-6 + 5y) - 3y = -5
x = - 6 + 5y

-12 + 10y - 3y = -5
x = - 6 + 5y

7y = 7 / : 7
x = - 6 + 5y

y = 1
x = - 6 + 5* 1

y = 1
x = -1
d)
3x-3y+3=0
x+0.5y-2=0

3x-3y+3=0
x = - 0, 5y + 2

3 * (-0,5y + 2) - 3y = -3
x = - 0, 5y + 2

-1,5y - 3y = -3 -6
x = - 0, 5y + 2

- 4,5y = -9 /: (-4,5)
x = - 0, 5y + 2

y = 2
x = - 0, 5 * 2 + 2

y = 2
x = 1