x + 195 + 231 = 2000158
=> x = 2000158 - 231 - 195
=> x = 1999732
x+195+231=2000158
x + 195 = 2000158 - 231
x + 195 = 1999927
x = 1999927 - 195
x = 1999732
x + 195 + 231 = 200158
x + 426 = 200158
x = 200158 - 426
x = 199732
x+195+231=2000158
x+195=2000158-231
x+195=1999927
x=1999927-195
x=1999732
x+195+231=2000158 Hoặc : x+195+231=2000158
x+426 =2000158 x +195 =2000158-231
x =2000158-426 x+195 =1999927
x =1999732 x =1999927-195
x =1999732
x+56+321=200456
x=200456-321=200135
x=200135-56=200079