Question 72476
3x - 2y = 7
-9x + 6y = -21
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Multiply the 1st equation by 3 to get:
9x - 6x = 21
Add that to the 2nd equation to get:
0+0 =0
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That means the two equations are the equation for the same line.
It means every point on the line is a solution, so there are 
infinitely many solutions to the system of equations. The equatios
are said to be dependent, meaning, one is a multiple of the other.
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Cheers,
Stan H.