\[\boxed{\mathbf{97}.}\]
\[1)\ 7 \cdot 9 + 78\ :13 = 72 + 6 = 78\]
\[2)\ 7^{3} - (128 + 172) =\]
\[= 343 - 300 = 43\]
\[3)\ (19 - 11)(19 + 11) =\]
\[= 8 \cdot 30 = 240\]