\(\huge\text{Hey there!}\)
\(\mathsf{4(2a)+7(-4b)+(3\times c \times5)}\\\mathsf{= 4(2a)+7(-4b)+3(c)(5)}\\\mathsf{= 8a - 28b + 3c(5)}\\\mathsf{= 8a - 28b + 15c}\\\\\huge\textbf{Thus, your answer is: \boxed{\mathsf{8a - 28b + 15c}}}\huge\checkmark\)
\(\huge\text{Good luck on your assignment \& enjoy your day!}\)
~\(\frak{Amphitritr1040:)}\)