Respuesta :
Answer:
51
Step-by-step explanation:
let's set the starting number as x
1. x times 2 = 2x
2. 2x- 138
3. result = 102
So, 2x-138 = 102
Now lets work backwards to solve for x.
1. 2x = 102
x = 51
So the starting number was 51.
Answer: 120
2x - 138 = 102
+138 +138
(x=the missing number)
2x =240
240\2 = 120
x=120
2x - 138 = 102
+138 +138
(x=the missing number)
2x =240
240\2 = 120
x=120
