Question

2x + y = -2
x + y = 5
The x-coordinate of the solution to the system shown is ___.
Possible answers:
-7
-3
3
7
Could anyone maybe explain the elimination method to me? Pretty please?

Answer 1

You want to eliminate an x or y (and later on a z)
To do that, you need to make one of the constants attached to one equation match the other.

Answer 2

http://www.coolmath.com/algebra/12-2x2-systems-of-equations/images/03-systems-02.gif

Answer 3

Thanks cx

Answer 4

In this case, you don't have to do anything but subtract the second equation from the 1st (the y's cancel out)

Answer 5

Thanks. My math teacher kept trying to explain it but...it apparently didn't go so well XP