Question

The solution to the system x + y = k

x - y = k is?

Answer 1

x+y=k--1
x-y=k--2
----------
2x=2k
=>x=k
now replace the value of x in equation 1
k+y=k
=>y=k-k
=>y=0

Answer 2

Okay.

Answer 3

I have 0= k-k....?