a) (x - 2005 ) . 2006 = 0
x - 2005 = 0 : 2006
x - 2005 = 0
x = 0 + 2005
x = 2005
b) 2005.(x-2006) = 2005
x - 2006 = 2005 : 2005
x - 2006 = 1
x = 1 + 2006
x = 2007
c) 480+45.4=(x+125) : 5 + 260
480 + 180 = (x+125) : 5 + 260
660 = ( x + 125 ) : 5 + 260
660 - 260 = ( x+ 125 ) : 5
400 = ( x + 125 ) : 5
400 x 5 = x + 125
2000 = x + 125
2000 - 125 = x
1875 = x
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