SOLUTION: Solve the system by addition or substitution. –6x + 3y = 12 y = 2x + 3

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Question 82405: Solve the system by addition or substitution.
–6x + 3y = 12
y = 2x + 3

Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
y=2x+3 now substitute (2x+3) for y in the other equation & solve for x.
-6x+3(2x+3)=12
-6x+6x+9=12
0x=12-9
0=3 now common solution here.
proof we plot the 2 lines
y=2x+3 (red line) &
3y=6x+12, y=6x/3+12/3, y=2x+4 (green line)
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+y+=+2x+%2B3%2C+y+=+2x+%2B4%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = 2x +3 and y = 2x +4).