pakai cara tolong ya!!!

[tex]x + 50 + x - 30 = 180 \\ 2x + 20 = 180 \\ 2x = 180 - 20 \\ 2x = 160 \\ x = 160 \div 2 \\ x = 80[/tex]
x= 80° (B)

semoga bermanfaat:)