8x=-72 | : 8 | x = -9
14+x=23| - 14 | x = 9
17=y-83 | + 83 | y = 100
8x+23=33 | - 23 | 8x = 10 | : 8 | x = 10/8 = 5/4
210-20x=230 | - 210 | -20x = 20 | :(-20) | x = -1
44=17a-7 | + 7 | 51 = 17a | :17 | a = 3
120-21x=9x | + 21x | 120 = 30x | : 30 | x = 4
-7x+4=x | + 7x | 4 = 8x | : 8| x = 4/8 = 1/2
Besten Gruß