Răspuns:
\begin{align*}
E(x) &= (3x+4)^2 + (1-x)(3x+7) - (2x-3)^2 - 8(4x+3) + 4 \\
&= (9x^2 + 24x + 16) + (3x+7 - 3x^2 - 7x) - (4x^2 - 12x + 9) - (32x + 24) + 4 \\
&= 9x^2 + 24x + 16 + 3x + 7 - 3x^2 - 7x - 4x^2 + 12x - 9 - 32x - 24 + 4 \\
&= 9x^2 + 3x^2 - 4x^2 + 24x + 3x - 7x + 12x - 32x + 16 + 7 - 9 - 24 + 4 \\
&= 8x^2 + 22x - 6 \\
&= 2(4x^2 + 11x - 3)
\end{align*}\begin{align*}
E(x) &= 2(4x^2 + 11x - 3) \\
&= 2(2x - 1)^2
\end{align*}