Question

SOLVE FOR X AND Y
3x+y=7
-4x-y=7

Answer 1

make a linear combo of the two equations: -x=14 => x=-14
Sub this value back into equation of your choice: 3(-14)+y=7 y=49
Answer: (-14, 49)

Answer 2

add to eliminate y:
-x = 14
x = -14
plug this into ist equation:

-42 + y = 7
y = 49

Answer 3

which one is right

Answer 4

both right

(x,y) = (-14,49)

Answer 5

adding both equations ==> -x=14==>x=-14 ==> subtituting in the 1st equation ==> y=49