\[(x + 4)^{2} - (x - 2)(x + 2) =\]
\[= x^{2} + 8x + 16 - x^{2} + 4 =\]
\[= 8x + 20;\]
\[при\ x = 0,125:\]
\[8 \cdot 0,125 + 20 = 1 + 20 = 21.\]