Question 703385
7x+2y=31 
x-y=-2 MULTIPLY BY 2 & ADD.
2X-2Y=-4
7X+2Y=31
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9X=27
X=27/9
X=3 ANS.
7*3+2Y=31
21+2Y=31
2Y=31-21
2Y=10
Y=10/2
Y=5 ANS.
PROOF:
3-5=-2
-2=-2