Решение:
\[ 0.8x - 4 - (-0.2x + 4) = 0 \]
\[ 0.8x - 4 + 0.2x - 4 = 0 \]
\[ (0.8x + 0.2x) + (-4 - 4) = 0 \]
\[ 1x - 8 = 0 \]
\[ x = 8 \]
Ответ: x = 8