Tolong dijawab pake cara,

2x + 84 = 5x - 12
2x - 5x = - 12 - 84
-3x = -96
x = 32

Besar sudut c = 2x -> 2(32) = 64
Jawabannya adalah pilihan (C).

sudut B = 180 - (5x-12)
= 180 - 5x + 12
= 192 - 5x
sudut segitiga BCD= sudut B+sudut C+sudut D
180 = 192-5x + 2x + 84
180 = 276 - 3x
3x = 276 - 180
x = 96/3
x = 32
sudut C = 2x = 2×32=64° (c)