Explicație pas cu pas:
A) 15x-10-48+78-13x = 128-48-62
2x-58+78= 80-62
2x+20 = 18
2x= - 2
X= - 1
B) 6x +8-10x+15+7=7x-7+4
- 4x +30=7x-3
Trecem 7x in stanga cu semnul schimbat
- 11x =-33
- X= - 11 ==> x=11
C) 6x-8 +30x-35-7x=16x+240-10
36x-7x - 43= 16x + 230
29x-43= 16 x +230
29x-16x = 230 +43
13x=273
X=21