Odpowiedź:
zad 15
a)
x/15 = 4/3
3x = 15 * 4
3x = 60
x = 60/3 = 20
b)
(3 - 2x)/12 = 3/2
2(3 - 2x) = 12 * 3
6 - 4x = 36
- 4x = 36 - 6
- 4x = 30
4x = - 30
x = - 30/4 = - 7 2/4 = - 7 1/2
c)
6/(2 - 3x) = 3/7 ; x ≠ 2/3
7 * 6 = 3(2 - 3x)
42 = 6 - 9x
9x = 6 - 42
9x = - 36
x = - 36/9 = - 4
d)
4/(1 - x) = 3/(1 + x ) ; x ≠ 1 i x ≠ - 1
4(1 + x) = 3(1 - x)
4 + 4x = 3 - 3x
4x + 3x = 3 - 4
7x = - 1
x = - 1/7
