Respuesta :

Answer:

D

Step-by-step explanation:

Since the weighing scale is balanced,

weight of the right side= weight on the left side

7(1)= 3x +1

7= 3x +1

Minus 1 on both sides:

3x= 7 -1

3x= 6

Divide both sides by 3:

x= 6 ÷3

x= 2

Thus, option D is correct.