1)x-480=529;x=520+480;x=1000
2)290+x=760;x=760-290;x=470
3)540-x=260;x=540-260;x=280
4)x-420=20;x=420+20;x=440
5)x+370=600;x=600-370;x=239
6)900-x=850;x=900-850;x=50
A+b+c=100
a=4
b=30
c=100-(a+b)
c=100-(4+30)
c=100-34
c=66 лет
8 : 2 = 4 - доп.множ. к 3/2 = (3*4)/(2*4) = 12/8 = 1 4/8
14 : 7 = 2 - доп.множ. к 2/7 = (2*2)/(7*2) = 4/14
84 : 21 = 4 - доп.множ. к 4/21 = (4*4)/(21*4) = 16/84