\[\boxed{\text{6.312.}}\]
\[\textbf{а)}\ 0,8548a + 0,1452a - 31,6 =\]
\[= a - 31,6\ \]
\[a = 360:\ \]
\[a - 31,6 = 360 - 31,6 = 328,4.\ \]
\[\textbf{б)}\ 88,8n - 66,6n + 4,44 =\]
\[= 22,2n + 4,44\]
\[n = 20:\ \]
\[22,2n + 4,44 =\]
\[= 22,2 \cdot 20 + 4,44 =\]
\[= 444 + 4,44 = 448,44.\ \]