Пошаговое объяснение:

72•1/2•(sin130°- sin30°)•sin110° = 36(sin130°- 1/2) • sin 110° = 36sin110°sin130°-18sin110° =36•1/2(cos -20° - cos240°) -18 sin(90°+20°)=18(cos 20°- (-1/2))-18cos20°= 18 (cos20°+1/2)-18cos20°=18cos20°+9-18cos20°=9