Solve the following equation:

$$
4 x(10 x-\{-10-[3 x-8(x+1)]\})+5\{12-[4(x+1)-3 x]\}=18 x^{2}-\left\{6 x^{2}-\left[7 x+4\left(2 x^{2}-x+11\right)\right]\right\}
$$
The right side can be written as (brackets expanded from the inside out):

$$
\begin{gathered}
4 x(10 x-\{-10+5 x+8\})+5\{12-x-4\}= \\
=4 x(5 x+2)+5(8-x)=20 x^{2}+3 x+40
\end{gathered}
$$

The left side (brackets expanded from the outside in):

$$
18 x^{2}-6 x^{2}+7 x+8 x^{2}-4 x+44=20 x^{2}+3 x+44
$$

Thus,

$$
20 x^{2}+3 x+40=20 x^{2}+3 x+44
$$

which, after rearrangement, yields the contradiction $0=4$. Therefore, there is no value of $x$ that satisfies our equation.

Maria Feledi (Esztergom, Dobó Katalin Secondary School I. o. t.)