y = 6x - 1 ------------------------(1)
y = 3x - 4 ----------------------(2)
substitute (1) in equation(2)
6x - 1 = 3x - 4
collect like term
6x - 3x = -4 + 1
3x = - 3
Divide both-side of the equation by 3
x = -1
substitute x = -1 into equation (2) and then solve for y
y = 3(-1) - 4
y = - 3 - 4
= -7
Hence