Question

Determine which system below will produce infinitely many solutions.

A. −6x + 3y = 18
4x − 3y = 6

B.2x + 4y = 24
6x + 12y = 36

C. 3x − y = 14
−9x + 3y = −42

D. 5x + 2y = 13
−x + 4y = −6

Answer 1

If one equation of the pair can be formed by multiplying the other by a constant then the 2 equations are the same and there are infinite solutions.
Note that the pair in option C falls into that category The second equation is formed form the first by multiplying by -3.

C is the answer