For this problem, I think the question is to find the values of x and y. Since there are two unknowns and two equations, this system may be solvable. But let's investigate first if the equations are independent.
y = 4x - 1 ----> eqn 1
12x = 3y + 7 ---> eqn 2
Substituting eqn 1 to eqn 2:
12x = 3(4x - 1) + 7
12x = 12x -3 + 7
12x - 12x = 7 - 3
0 = 4
It turns out that the system is not solvable because x cancels out. That means that the two given equations are dependent with each other.