Odpowiedź:
zad 13
a)
(2x + 3)/5 = (2 - x)/3 - x | * 15
3(2x + 3) = 5(2 - x) - 15x
6x + 9 = 10 - 5x - 15x
6x + 9 = 10 - 20x
6x + 20x = 10 - 9
26x = 1
x = 1/26
b)
(x + 1)/2 - (x - 1)/3 = 1/4 | * 12
6(x + 1) - 4(x - 1) = 3
6x + 6 - 4x + 4 = 3
2x + 10 = 3
2x = 3 - 10 = - 7
x = - 7/2 = - 3,5
c)
(4x + 7)/2 - (5x - 1)/6 = x + 5 | * 6
3(4x + 7) - 5x + 1 = 6(x + 5)
12x + 21 - 5x + 1 = 6x + 30
7x + 22 = 6x + 30
7x - 6x = 30 - 22
x = 8
d)
(x + 5)/4 - (2x + 1)/8 = 1/2(2 - x) | * 8
2(x + 5) - 2x - 1 = 4(2 - x)
2x + 10 - 2x - 1 = 8 - 4x
10 = 8 - 4x
4x = 8 - 10
4x = - 2
x = - 2/4 = - 1/2
