Answer:
[tex] \: \: \: \: \: \: \:\: 13v + ( - 14v) - 9 = 6 \\ = > 13v - 14v - 9 = 6 \\ = > - v - 9 = 6 \\ = > - v = 6 + 9 \\ = > - v = 15 \\ = > v = - 15[/tex]
Verification :
[tex]\:\:\:\:\:\:\:\:13v+(-14v)-9 =6\\=>13×(-15)+[-14×(-15)]-9 = 6\\=>-195+210-9=6\\=>-204+210=6\\=>6=6 [/tex]