Question 53284: Will you please solve the system by subtraction
3x-y=-7
x+y=-9
thankyou
Answer by funmath(2933)   (Show Source):
You can put this solution on YOUR website! You can solve this by adding the two equations together and eliminating the y's then solve for x:
3x-y=-7
x+y=-9
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4x+0y=-16
4x=-16
4x/4=-16/4
x=-4
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Now substitute x=-4 into the second equation (it's the easier of the two) and solve for y:
-4+y=-9
+4-4+y=-9+4
y=-5
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Your solution is: (-4,-5)
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You can check this by substituting these values into both equations and see if it checks:
3(-4)-(-5)=-7
-12+5=-7
-7=-7 I think we're right!
(-4)+(-5)=-9
-9=-9 I know we're right!!!!!
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