SOLUTION: Can somebody please help me? Solve by substitution. 8x-4y=16 y=2x-4 Thanks

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Question 93896: Can somebody please help me?
Solve by substitution.
8x-4y=16
y=2x-4
Thanks
Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
Y=2X-4 NOW SUBSTITUTE (2X-4) FOR Y IN THE OTHER EQUATUION & SOLVE FOR X.
8X-4(2X-4)=16
8X-8X+16=16
0X=16-16
0=0
THIS SAYS THE 2 EQUATIONS ARE IDENTICAL. 2 UNKNOWNS IN ONE EQUATION HAS NO UNIQUE SOLUTION.
PROOF BY GRAPHING AS FOLLOWS:
Y=2X-4 (RED LINE)
8X-4Y=16 OR -4Y=-8X+16 OR Y=-8X/-4+16/-4 OR Y=2X-4 (GREEN LINE).
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+y+=+2x+-4%2C+y+=+2x+-4%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = 2x -4 and y = 2x -4).