SOLUTION: I am lost Solve the system by substitution. 3x – y = –7 x + y = –9

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Question 94507: I am lost

Solve the system by substitution.
3x – y = –7
x + y = –9
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
from first equation 3x+7=y ... using second equation x+(3x+7)=-9 ... 4x+7=-9 ... 4x=-16 ... x=-4

3(-4)-y=-7 ... -12+7=y ... -5=y