Exercițiul 370

E.370. Aflați numărul natural xx din egalitatea:
34232+{20180+23+71[5322(103+32):x]}=2017201820172.34^2-3^2+\{2018^0+2^3+7^1 \cdot [5^3-2^2 \cdot (10^3+3^2):x]\} = 2017 \cdot 2018 - 2017^2.

Olimpiadă, etapa locală, Timiș, 2018

Răspuns: x=2018.x=2018.

Soluție:

11569+{1+8+7[1254(1000+9):x]}=2017(20182017).1156-9+\{1+8+7 \cdot [125-4 \cdot (1000+9):x]\} = 2017(2018 - 2017).
11569+{1+8+7[1254(1000+9):x]}=2017(20182017).1156-9+\{1+8+7 \cdot [125-4 \cdot (1000+9):x]\} = 2017(2018 - 2017).
1147+[9+7(12541009:x)]=2017.1147+[9+7 \cdot(125-4 \cdot 1009:x)]=2017.
9+7(12541009:x)=8709+7 \cdot(125-4 \cdot 1009:x) = 870
7(12541009:x)=8617 \cdot(125-4 \cdot 1009:x)=861
12541009:x=123125-4 \cdot 1009:x = 123
241009:x=02-4 \cdot 1009:x = 0
41009:x=24 \cdot 1009:x = 2
x=21009x=2018.x=2 \cdot 1009 \Rightarrow \boxed{x=2018}.