231 - ( x - 6 ) = 1339 : 13
231 - ( x - 6 ) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
2 . x - 138 = 23 . 32
2 . x - 138 = 8 . 9
2 . x - 138 = 72
2 . x = 72 + 138
2 . x = 210
x = 210 : 2
x = 105
231 - ( x - 6 ) = 1339 : 13
231 - (x - 6) = 1339/13
x - 6 = 231 - 1339/13
x - 6 = 128
x = 128 + 6
x = 134