8
x + y = 4 multiple 2 on both sides:
2x + 2y = 8 equation 1;
x - 2y = -5 equation 2;
Adding up equation 1 and equation 2,
3x = 3
x + y = 4, x - 2y = -5 If the first equation is multiplied by 2 and then the equations are added, the result is 3x = 3.
Added 4/29/2014 8:57:06 PM
This answer has been confirmed as correct and helpful.
Confirmed by
jeifunk [4/29/2014 9:04:42 PM]