SOLUTION: Y = 2X + 9 2X - Y = -9 USE SUBSITUTION

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Question 246615: Y = 2X + 9
2X - Y = -9 USE SUBSITUTION
Answer by dabanfield(803) About Me  (Show Source):
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Y = 2X + 9
2X - Y = -9 USE SUBSITUTION
Since Y = 2X +9 in the first equation substitute 2X+9 for Y in the second equation:
2X-Y = -9
2X-(2x+9) = -9
2X-2X-9 = -9
-9 = -9
So all values of X and, consequently, Y are solutions to these two equations.