Tolong dong kak plis sebisanya aja ko no 1 aja jg gpp​

Penjelasan dengan langkah-langkah:

1. 4x + 2x = 90

6x = 90

x = 15

2. 3x + 3x + 3x = 180

9x = 180

x = 20

3. 20 + x + 90 = 180

x = 180 – 20 – 90

= 70