Question

Solve x + 2y = 13
4x + 8y = –9

Answer 1

Stack them so the x's and y's line up:

x + 2y = 13
4x + 8y = –9

Answer 2

now we want to be able to add the 2 equations and get a new equation but we want either the x's or the y's to add up to zero.
We need EITHER the numbers in front of the x's to be the same
OR the numbers in front of the y's to be the same BUT OPPOSITE SIGNS

Answer 3

oh ok

Answer 4

so there is no solution to this equation

Answer 5

You are correct because you wind up with 0 equals some other number which is nonsense.
If you get something that is always true, like 2 = 2, then there are an infinite number of solutions.