2x-138=23.32
2x-138=72
2x=72+138
2x=210
x=210:2
x=105
231-(x-6)=1339:13
231-(x-6)=103
x-6=231-103
x-6=128
x=128+6
x=134
A) 2.x-138=23.32
2.x-138=8.9
2.x-138=81
2.x =81+138
2.x =219
x=219:2
x=109,5
B) 231-(x-6)=1339:13
231-(x-6)=103
x-6 =231-103
x-6 =128
x =128+6
x=134
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
bn nhớ cho mk nha!