SOLUTION: using substitution: x=-y-1 and x-y=-11

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Question 620217: using substitution: x=-y-1 and x-y=-11
Answer by math-vortex(648) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, there--
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Use the Substitution method to solve this system of equations:
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x=-y-1
x-y=-11
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Substitute -y-1 for x in the second equation. (We can make this move because the first equation tells us that whatever x is, it is equal to -y-1.)
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x-y=-11
%28-y-1%29-y=-11
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Simplify by combining like terms.
-2y-1=-11
-2y=-10
y=5
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Substitute 5 for y in the first equation.
x=-y-1
x=-%285%29-1
x=-6
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According to our algebra, x=-6 and y=5. Thus the ordered pair (-6,5) is the solution to this system of equations. If you graphed these equations you would see two lines intersecting at (-6,5).
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Last step, check the solution in both equations. (It's very east to make an error.)
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x=-y-1
(-6)=-(5)-1
-6=-6
Check!
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x-y=-11
(-6)-(5)=-11
-11=-11
Check!
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Feel free to email me if you still have questions about this.
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Ms.Figgy
math.in.the.vortex@gmail.com