We live in 2014!

2014 2014 can be written as: a 3 a 2 a 1 a 0 a^3-a^2-a^1-a^0 for a N a\in\mathbb{N} . Determine the value of a a .


The answer is 13.

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5 solutions

Vitor da Silva
May 4, 2014

The problem gives us a³-a²-a¹-a⁰=2014. We can rewrite it as a³-a²-a-2015=0. The natural solution to this equation must be a multiple of 2015, which is divisible by 5,13 and 31. The number that satisfies the equation is 13, so... 13.

Anoir Trabelsi
May 4, 2014

a^3 - a² - & - 2015 = 0 then use the rational root theorem to find that 13 is a root for this equation . It can be written as ( a - 13) ( a² + 12a + 155) . The only solution is a = 13 :)

a 3 a 2 a 1 = 2014 a^{3}-a^{2}-a-1=2014
a a must be > 10 since 1 0 3 = 1000 10^{3}=1000 and a a < 15 since 1 5 3 = 3375 15^{3}=3375
trying for a a =11 to 14, we know that 13 was the answer.
and also, if you notice that a 3 a 2 a = 2015 a^{3}-a^{2}-a=2015 , the last digit is 5, without doing calculation ( I mean simple ), we can directly know that 13 was the answer since 3 3 3 2 3 = 15 3^{3}-3^{2}-3=15 also has 5 as the last digit


13^3-13^2-13^1-13^0=2014 I got it......

Arjun Chotaliya
May 4, 2014

its 13 obvious every no can be obtain preceding its no

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