Answer FULLY and get CORRECT $2$ Resistor Bridge

Consider the following circuit. This is the kind of circuit we could solve with a $Y$ transformation, but here we will consider it using Th$$venin $($or Norton$)$ equivalents.

Answer the following questions:

$($a$).$ If resistor $R_x$ is replaced by an open circuit $($or$,$ alternatively, consider $R_x),$ what is the voltage $v_x(1$ mark$)?$

$($b$).$ If resistor $R_x$ is replaced by a short circuit $($or$,$ alternatively, consider $R_x=0),$ what is the current $i_x(1$ mark$)?$

$($c$).$ If resistor $R_x$ is set to $R_x=6\mathrm{.}2k$ as shown in the original circuit, what is the current $i_x(1$ mark$)?$

$($d$).$ If resistor $R_x$ is replaced by a current source that sets $i_x=-2mA,$ then what is the new voltage $v_x?(1$ mark$)?$

Hint: Your answers to $($a$)$ and $($b$)$ provide enough information to replace everything except $R_x$ with either a Th$$venin or Norton equivalent $($your choice, they both do the same thing$),$ and that will make solving $($c$)$ and $($d$)$ very straightforward. Of course you can also solve the full circuit for $($c$)$ and $($d$),$ or even use MicroCap $-$ I won't know the difference.