Question

Which of the system(s) below works best to solve by elimination? Why? System 1 : 3m+n=71 2m-n=30

System 2 : 4x+y=1 y=-2x+9
System 3 : 5x+4y=15 5x + 11y=22

Answer 1

first option is easiest since it involves just adding both equations term by term.

3m+n=71

2m-n=30

Explanation:

The first system looks like the easiest one, because the two equations are listed already in standard form, and the variable "n" appears as positive "n" in the first equation, and as its opposite "-n" in the second equation. Therefore the elimination method works directly by adding both equations term by term (thus cancelling out completely one of the variables in the resultant/combined equation.