Question 505274
X+3y=7 .................(1)
X-3y=-5 ................(2)

Add both equations

X+3y=7 
X-3y=-5 
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2X=2
Divide by 2 both sides of above equation
2X/2=2/2
X=1

Put the value of X in (1)

X+3y=7
1+3y=7
Subtract 1 from both sides of the equation
1-1+3y=7-1
3y=6
Divide by 3 both sides of above equation
3y/3=6/3
y=2

Solution set (1, 2)

Check
Put the value of X and y in (1)
X+3y=7 .................(1)
1+3(2)=7
1+6=7
7=7

Put the value of X and y in (2)
X-3y=-5 ................(2)
1-3(2)=-5
1-6=-5
-5=-5