we have that
case 1)
system of equations is
y=−12x−1
y=14x−4
using a graph tool
see the attached figure
the solution of the system is the point (0.115,-2.385)
case 2)
system of equations is
blue line passing through coordinates A (0, -4) and B (4, -3)
red line passing through coordinates C(0, -1) and D (4, -3)
using a graph tool
see the attached figure
the solution of the system is the point (4,-3)