\[\boxed{\text{5.\ 35}}\]
\[\textbf{а)} - 3p \cdot ( - 2,3) = 6,9p \rightarrow 6,9\]
\[\textbf{б)} - 4,3m \cdot ( - 2) = 8,6m \rightarrow 8,6\]
\[\textbf{в)} - 0,23x \cdot ( - 3m) =\]
\[= 0,69xm \rightarrow 0,69\]
\[\textbf{г)} - 17,9ab \cdot ( - 1) =\]
\[= 17,9ab \rightarrow 17,9\]