Răspuns:
Explicație pas cu pas:
a)
[2 × ( X + 2 ) × 5 + 3 × ( X + 2 ) ] × 7 = 273
10 x + 20 + 3 x + 6 = 273 : 7
13 x + 26 = 39
13 x = 39 - 26
13 x = 13
x = 13 : 13
x = 1
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b)
2004 + 2004 × 2005 - 2003 × 2006 = 2006
= 2004 × ( 1 + 2005 ) - 2003 × 2006 =
= 2004 × 2006 - 2003 × 2006 =
= 2006 × ( 2004 - 2003 ) =
= 2006 × 1 =
= 2006
