Answers

2014-11-10T21:19:30+08:00
The equations must be satisfied when the rdered pairs are plugged in.  For example, to know if the ordered pair (2,2) satisfies the system of equations:

x + y = 4
x - y = 0

then, 2 + 2 must equal 4, and 2-2 must equal 0
1 4 1