Question

Oblicz x.

a) 0,2x+5(2,2-0,2x)=(3x-10)0,2-1

20-(28-0,4x)5=2x+4(10-2x)

20=5(4x-7)-(34,2-1,8x):0,36

b) 6(7x+20)+30=(500+100x):5-60

13(x-2)-(96-6,4x):0,8=1

163+2x=5+(70,4x-134,4):3,2

Answer 1

a)
0,2x+5(2,2-0,2x)=(3x-10)0,2-1
0,2x + 11 - x = 0,6x - 2 - 1
-0,8x + 11 = 0,6x - 3
-0,8x - 0,6x = -3 -11
-1,4x = -14      | : -1,4
x = 10
______________________

20-(28-0,4x)5=2x+4(10-2x)
20 - 140 + 2x = 2x +40 - 8x
-120 + 2x = -6x + 40
2x + 6x = 40 + 120
8x = 160    | :8
x = 20
___________________________

20=5(4x-7)-(34,2-1,8x):0,36
20 = 20x - 35 - 95 + 5x
20 = 25x - 130    | + 130
150 = 25x    | : 25
6 = x
x = 6
____________________________________

b)
6(7x+20)+30=(500+100x):5-60
42x + 120 + 30 = 100 + 20x - 60
42x +150 = 40 + 20x
42x - 20x = 40 - 150
22x = - 110    | : 22
x = - 5
___________________________

13(x-2)-(96-6,4x):0,8=1
13x - 26 - 120 + 8x = 1
21x - 146 = 1      | + 146
21x = 147    | : 21
x = 7
_____________________________

163+2x=5+(70,4x-134,4):3,2
163 + 2x = 5 + 22x - 42
2x = 5 - 42 - 163
2x = - 200      | : 2
x = - 100

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