Answer: Â Infinitely many solutions
The solutions are of the form (x,y) = (x,3x+5) for any real number x.
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Explanation:
Plug the first equation into the second. We'll replace y with 3x+5
12x-4y = -20
12x-4( y ) = -20
12x-4(3x+5) = -20 .... y replaced with 3x+5
12x-12x-20 = -20
0x-20 = -20
0-20 = -20
-20 = -20
We end up with a true equation no matter what x is.
Therefore, this system has infinitely many solutions.
Each solution is of the form (x,y) = (x,3x+5) because y = 3x+5.
