\[77(a - 1) + 23(a + 5) =\]
\[= 77a - 77 + 23a + 115 =\]
\[= 100a + 38;\]
\[a = 7,941:\]
\[100 \cdot 7,941 + 38 =\]
\[= 794,1 + 38 = 832,1.\]