Question

How do you solve using elimination of `2x+y=4` and `-2x-y=4`?

Answer 1

The equations have no solutions!

Explanation:

If `(x,y)` had existed that satisfied

`2x+y=4` and `-2x-y=4`,

adding them would yield the contradiction

`0=8`

So, no such `(x,y)` can exist.

Alternatively, the two equations represent two straight lines that have the same slope (namely, -2 ) and different intercepts (4 and -4, respectively). So, they are parallel lines that never intersect.