а=19-b
(19-b+7)+(b-7)=12-b+b-7=5
А) a*b:c
-900*60:(-3)=-900*(-20)=18000
б) a:b*c
-900:60*(-3)=-15*(-3)=45
в) a*(b:c)
-900*(60:(-3))=-900*(-20)=18000
г) a:(b*c)
-900:(60*(-3))=-900:(-180)=5
А)14x+27x=656
41x=565
x=656:41
x=16
б)81y-38y=645
43y=645
y=645:43
y=15
14x+27x=656
41x = 656
x = 16