Question

How to solve 3x+2y=-1, 6x+4y=0 by elimination

Answer 1

(1) 3x+2y=-1
(2) 6x+4y=0

This system of equation has no solution. Proof
multiply all the term of (1) by two ==>6x+4y=-2
Notice that in (2) you have the same thing but equal to zero.
Same quantity can't equal 0 & -2. So no solution