The best variable to solve is x=3-2v, after dividing the first equation by 3.
x=4, and v=-1/2
1) Solving that system by Substitution
2) Making then
x=3-2v
2x-10v=13
3) Plugging into the 2nd equation
2(3-2v)-10v=13
6-4v -10v=13
6-14v=13
-14v=13-6
-14v=7
v=-1/2
Plugging into the first equation
x=3-2v
x=3-2(-1/2)
x=3+1
x=4
