Check the picture below.
[tex](8v+12)+(11v-3) = 180\implies 19v+9=180\implies 19v = 171 \\\\\\ v = \cfrac{171}{19}\implies \boxed{v = 9} \\\\[-0.35em] ~\dotfill\\\\ (8v+12)+(7x+12) = 180\implies (8\stackrel{v}{(9)}+12)+(7x+12) = 180 \\\\\\ (\stackrel{8v}{72}+12)+(7x+12) = 180\implies 72+24+7x=180\implies 96+7x=180 \\\\\\ 7x=84\implies x = \cfrac{84}{7}\implies \boxed{x = 12}[/tex]
