In this question there is 1 equation with 1 unknown variable. So it is absolutely possible to find the value of the unknown variable "x".
(4x - 1)/3 = 7/1
4x -1 = 7 * 3
4x - 1 = 21
4x = 21 + 1
4x = 22
x = 22/4
= 11/2
So the value of the unknown variable x is 11/2. So the correct option is option "d". Hope i have answered your question correctly and helped you to understand the method by which these problems should be done.
