Question

Determine which system below will produce infinitely many solutions.

1. −6x + 3y = 18
4x − 3y = 6

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

3. 3x − y = 14
−9x + 3y = −42

4. 5x + 2y = 13
−x + 4y = −6

Answer 1

For this one the answer is the equation:
3x - y = 14
-9x + 3y = -42

3x - y = 14.....multiply by 3
-9x + 3y = -42
------------------
9x - 3y = 42 (result of multiplying by 3)
-9x + 3y = -42
-----------------add
0 = 0 (correct...infinitely many solutions)