Odpowiedź:
A) 3x + 6 = 21 /-6
3x = 15 /:3
x = 5
3 * 5 + 6 = 15 + 6 = 21
B) 2x + 3 = 13 /-3
2x = 10 /:2
x = 5
2 * 5 + 3 = 10 + 3 = 13
C) 8 - 6x = -8x
-8x = 8 - 6x
-8x + 6x = 8
-2x = 8 /:(-2)
x = -4
8 - 6 * (-4) = 8 + 24 = 32
-8x = -8 * (-4) = 32
D) 6 - 5x = 29 /-6
-5x = 23 /:(-5)
x = - 4 3/5
6 - 5 * (-23/5) = 6 + 23 = 29
