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2010-04-13T19:23:28+02:00
Zadanie 14
a) x + 5 = 10
x = 10 - 5 = 5
b) 2x + 3 = 15
2x = 15 -3
2x = 12 /:2
x = 6
c) 5x + 13 = 23
5x = 23 - 13
5x = 10 /:5
x = 2
d) 3x + 11 = 41
3x = 41 - 11
3x = 30 /:3
x = 10
e) -x + 2 = 8
-x = 8 - 2
-x = 6 /: (-1)
x = 6
f) -x + 5 = -2
-x = -2 - 5
-x = -7 /: (-1)
x = 7
g) -2x - 7 = 11
-2x = 11 + 7
-2x = 18 /: (-2)
x = -9
h) -5x + 3 = -12
-5x = -12 - 3
-5x = -15 /: (-5)
x = 3

zadanie 15
a)
2(x+3) = 10
2x + 6 = 10
2x = 10 - 6
2x = 4 /: 2
x = 2
b) 3(x-1) + 2 = 8
3x - 3 + 2 = 8
3x = 8 + 3 - 2
3x = 9 /: 3
x = 3
c) 2(13-x) - 9 = 1
26 - 2x - 9 = 1
-2x = -16 /: (-2)
x = 8
d) 3(1-x) + 2 = -7
3 - 3x + 2 = -7
-3x = -12 /: (-3)
x = 4
e) 3(x+3) = 2(x+4) + x + 1
3x + 9 = 2x + 8 + x +1
0 = 0
f) 4(3x+2) + 5(2x+3) = -(2x+13)
12x + 8 + 10 x + 15 = -2x - 13
20x = -36 /: 20
x = -1,8
g) 4(x-2) -2(x-4) = 5(x+1) - 3x
4x - 8 - 2x + 8 = 5x + 5 - 3x
0 = 5
h) 2(x-4) = 2(2x-1) + 6(x+1)
2x - 8 = 4x - 2 + 6x + 6
-8x = 12 /: (-8)
x = -1,5