Answer:
[tex]40c^{-11}d^4[/tex]
Step-by-step explanation:
[tex](-5c^{-7}d^3)(8c^{-4}d^1)= \\\\(5\cdot 8)(c^{-7}\cdot c^{-4})(d^3 \cdot d^1)= \\\\(40c^{-11}d^4)[/tex]
Hope this helps!