Using a decoder like the one shown in PowerPoint slide set #$10($Multiplexers and Decoders$)$ page

$5$ and one OR gate with an appropriate number of inputs, show how you could

a$)$ Implement the circuit necessary to appropriately light the $"$e$"$ segment of the $7-$segment display

D

b$)$ Implement the circuit necessary to appropriately light the $"$f$"$ segment of the $7-$segment display