Question

What are x and y if `-3x+y=6` and `6x-2y=25?`?

Answer 1

It is impossible for both
`color(white)("XXX")-3x+y=6`
and
`color(white)("XXX")6x-2y=25`
for any pair of values `(x,y)`

Explanation:

Given
[1]`color(white)("XXX")-3x+y=6`
and
[2]`color(white)("XXX")6x-2y=25`

If we multiply [1] by `(-2)`, we get
[3]`color(white)("XXX")6x-2y = -12`

Comparing [2] and [3], we have
`color(white)("XXX")25 = -12` (Impossible)

The given equations represent two parallel lines (they have no points in common).