yg jago mtk, please jawab dong pake cara 3x+50°

Bab Garis dan Sudut

∠BLK + ∠CMN = 180°
2x + 40 + 3x + 50 = 180
5x = 180 - 90
x = 90/5
x = 18°

∠ALM = ∠BLK
∠ALM = 2(18) + 40
∠ALM = 36 + 40 = 76° [C]