X + 58 =204
X = 204 -58
X = 196
a, X + 58 = 79 + 125
X + 58 = 204
X = 204 - 58
X = 146
Vậy X = 146
b, X x 25 = 124 - 24
X x 25 = 100
X = 100 : 25
X = 4
Vậy X = 4
c, X + 12345 = 24897
X = 24897 - 12345
X = 12552
Vậy X = 12552
Hok tốt !
x + 58 = 79 + 125
x + 58 = 204
x = 204
x x 25 = 124 - 24
x x 25 = 100
x = 100 : 25
x = 4
x + 12345 = 24897
x = 23897 - 12345
x = 11552