solve the linear system 4x-y+12=0 3x-y+6=0

We'll re-write the equations of the system, isolating the
variable y to the left side:

The equations
are:

y = 4x + 12 (1)

y = 3x +
6 (2)

We'll put (1) = (2)

4x +
12 = 3x + 6

We'll isolate x to the left side. For this
reason, we'll subtract 3x both sides:

4x - 3x + 12 =
6

x + 12 = 6

We'll subtract 12
both sides:

x = -12 + 6

x =
-6

We'll substitute x in
(2):

y = 3*(-6) + 6

y = -18 +
6

y =
-12

The solution of the system is: (-6 ,
-12).