How do you substitute 3x-12y=-6 and x-4=-8?

x - 4 = - 8 add 4 to both sides

x = - 4

Put the value of x to the first equation 3x - 12y = - 6:

3 (-4) - 12y = - 6

-12 - 12y = - 6 add 12 to both sides

-12y = 6 divide both sides by (-12)

y = - 0.5

Answer: x = - 4 and y = - 0.5

New question:

x - 4y = - 8 add 4y to both sides

x = 4y - 8

Substitute it to the first equation:

3 (4y - 8) - 12y = - 6 use distributive property

(3) (4y) + (3) (-8) - 12y = - 6

12y - 24 - 12y = - 6

-24 = - 6 FALSE

Answer: No solution.