Tolong dijawab nomor 21 pakai cara ya ​

Jawaban Terlampir. Semoga Membantu.

20. 3x – 20° + 2x = 180°

5x – 20° = 180°

5x = 180° + 20°

5x = 200°

5x = 40°

21. 3x – 20° = 3(40°) – 20°

= 120° – 20°

= 100°