Quick digital logic question

[Sarevok]

Suppose you were implementing a boolean function using a MUX. Say it is a four variable function F(a,b,c,d)=abc+ab'c+abd+bc+ab'd.

Now the rule is that you make a 8x1 line MUX. And apply a,b,c as selection input signal and d as data signal.

My question is can you apply b,c,d or a,c,d or something else other than a,b,c as selection input ?

[Starglider]

My question is can you apply b,c,d or a,c,d or something else other than a,b,c as selection input ?

In general you'd need a different connection pattern for the inputs, unless the variables are reversible. Using a 3-bit multiplexer effectively turns a single function with a 4-bit domain and range into a set of eight 1-bit functions. Those functions are implemented by connecting the appropriate multiplexer inputs to high, low, d, or inverted d. However in this case your function seems to be (a&b)|(b&c), unless I am reading it wrong, which means you can ignore d entirely - or just forget using a MUX and implement it with two logic gates as (a|c)&b.