+241 Well, for substitution, it's very simple:
3x + 6(-5) = -18
3x + (-30) = -18
3x = 12
x = 4
Then, for elimination it would be:
(-7x + 9y = -19)
+ (4x -9y = 10)
------------------------
-3x = -9
x = 3
And finally, for the other elimination:
(-5x + 8y = -4)
+ (6x - 8y = -12)
---------------------
x = -16
I am not sure if this is the "right" kind of elimination, but it works!
