8. \(\alpha = 20^{\circ}\), \(\beta = 40^{\circ}\), \(\angle 1 = ?\), \(\angle 2 = ?\)

Угол, смежный с углом \(\alpha\), равен \(180^{\circ} - 20^{\circ} = 160^{\circ}\). Угол, смежный с углом \(\beta\), равен \(180^{\circ} - 40^{\circ} = 140^{\circ}\). \(\angle 1\) равен сумме смежных углов с \(\alpha\) и \(\beta\) \(\angle 1 = 160^{\circ} + 140^{\circ} = 300^{\circ}\). Значит \(\angle 2 = 360^{\circ} - 300^{\circ} = 60^{\circ}\). Ответ: \(\angle 1 = 300^{\circ}\), \(\angle 2 = 60^{\circ}\)