Question

помогите уравнение пожалуйста

Answer 1

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

Answer 2

(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=4+25
580÷b=29
b=580÷29
b=20
Проверка
(580÷20-25)×90+490=850
850=850