How do i solve this system of linear equation?
4x-2y=12
-4x-9y=54

If i am correct it should come out to be -6 i hope this helps 4-4 drop the x 9-2 =-7 12 - 54 bc you drop it down making it a negative is 42 then 42/-7= -6

4x-2y = 12(i)
+
-4x-9y = 54(ii)
                            Lets eliminate x, by adding (i) and (ii). 
0x -11y = 66

-11y = 66

y = 66/-11

y = -6

Let us substitute y = -6 into (i)

4x - 2y = 12

4x - 2*(-6) =12

4x + 12 = 12

4x = 12 - 12

4x = 0

x = 0/4

x = 0

Therefore x = 0, and y = -6

Hopes this helps.