Im having trouble understand the mapping rule with functions, like how would I figure out the mapping rule of:
f(x)=3x-5
and
f(x)= -1/2x + 3
i know like the y=mx+b mapping rule but cant figure out how to reverse that and do it with function, if someone could explain itd be great, thanks

Sorry if it seems like I'm just looking for an easy answer but all resources I found online were strictly for quadratics which I know, not functions