Question 1040810
Let's call the equations A and B

A: 3x+y = 9
B: 3x-5y = 15


Subtract the equations A - B. To do this, we subtract the like terms on each side
3x - 3x = 0x = 0. The x terms go away
y - (-5y) = y+5y = 6y
9-15 = -6



So after subtracting the equations (A-B) we end up with 6y = -6


Now we divide both sides by 6 to fully isolate y


6y = -6
6y/6 = -6/6
y = -1


Now use this to find x


3x+y=9
3x+(-1)=9 ... replace y with -1
3x-1 = 9
3x-1+1 = 9+1
3x = 10
3x/3 = 10/3
x = 10/3


So,
x = 10/3
y = -1


The solution as an ordered pair is (10/3, -1)