200-(48*b) *45=20 | уравнение решите 55

200 - ( 48 × b ) × 45 = 20
200 - 48b × 45 = 20
200 - 2 160b = 20
- 2 160b = 20 - 200
- 2 160b = - 180
b = - 180 ÷ ( - 2 160 )
b = 180/2 160
b = 180 ÷ 180 / 2 160 ÷ 2 160
b = 1/12.

200-(48*b)*45=20
200-48b*45=20
200-2160b=20
2160b=180
b=1/12