(580:b-25)*90+490=850 Решите уравнение!

Question

(580:b-25)*90+490=850
Решите уравнение!

Answer 1

(580:b-25)*90+490=850
(580:b-25)*90=850-490
(580:b-25)*90=360
580:b-25=360:90
580:b-25=4
580:b=25+4
580:b=29
b=580:29
b=20

Answer 2

(580:b-25)*90+490=850
580:b-25=850-490/90
580/b-25=4
580/b=29
b=20