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a fost răspuns

Aflati x :
a). 2^{x} + 2^{x+1} + 2^{x+2} <112

Răspuns :

Vic04usea
am considerat x=n....

2ⁿ + 2ⁿ†¹ + 2ⁿ†² < 112
2ⁿ + 2ⁿ·2¹ + 2ⁿ·2² < 112
2ⁿ(1+2¹+2²) < 112
7·2ⁿ < 112
2ⁿ < 112/7
2ⁿ < 16
2ⁿ < 2⁴
n < 4
n apartine (-∞;4)