a) 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
b) 231 - ( x - 6 ) = 1339 : 13
231 - ( x - 6 ) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a, 2x-138=32.9
2x-138=288
2x=288+138
2x=426
x=213
b, 231-(x-6)=103
x-6=231-103
x-6=128
x=134