There are \(15\) cities in Wonderland, a foreigner was told that every city is connected with at least seven others by a road. Is this enough information to guarantee that he can travel from any city to any other city by going down one or maybe two roads?
Solve the equation: \(|x-2005| + |2005-x|=2006\).
Two different numbers \(x\) and \(y\) (not necessarily integers) are such that \(x^2-2000x=y^2-2000y\). Find the sum of \(x\) and \(y\).
Is it possible for the mean of some 35 whole numbers to equal \(6.35\)?
Find \(x^3 +y^3\) if \(x+y=5\) and \(x+y+x^2 y +xy^2 =24\).
On the \(xy\)-plane shown below is the graph of the function \(y=ax^2 +c\). At which points does the graph of the function \(y=cx+a\) intersect the \(x\) and \(y\) axes?
Find the largest natural number \(n\) which satisfies \(n^{200} <5^{300}\).
Solve the following inequality: \(x+y^2 +\sqrt{x-y^2-1} \leq 1\).
Is it true that, if \(b>a+c>0\), then the quadratic equation \(ax^2 +bx+c=0\) has two roots?
Suppose that: \[\frac{x+y}{x-y}+\frac{x-y}{x+y} =3.\] Find the value of the following expression: \[\frac{x^2 +y^2}{x^2-y^2} + \frac{x^2 -y^2}{x^2+y^2}.\]