2.
(6x/(22/15)) =(86/10)/(172/100)
(6x/(22/15)) =(86/10)*(100/172)
(6x/(22/15)) =(8600/1720)
(6x) =(8600/1720)*(22/15)
x= ((5)*(22/15))/6
x= ((110/15))/6
x= ((110/15)*1/6)
Ответ : x= 110/90 = 11/9 = 1целая2/9
3.
a/c=b/d
a=bc/d
a+9c=bc/d +9c
(a+9c)/c = b/d+9
(a+9c)/c = b/d+9d/d
(a+9c)/c = (b +9d)/d