it appears to me that the current generated by 35 V and 2vx will
collide each other
It may be that you are assuming that a voltage source, whether independent or controlled, must source current, i.e., supply power to the circuit.
But, at least in ideal circuit theory, there's nothing "wrong" with a voltage source sinking current, i.e., receiving power from the circuit.
For a real world example, consider that, when a battery is being charged, the current is in the opposite direction than when the battery is being discharged.
I would like to know how the current flows across 5 Ω resistor.
If you're planning to be an EE, don't write or say things like "current across"; current is through, voltage is across.
Now, this circuit is very easy to solve. There are two unknowns so you need two independent equations.
For the 1st, write a KVL equation clockwise 'round the loop:
$$35V = v_x + 2v_x - v_o \rightarrow 3v_x = 35V + v_o$$
Now, you need one more independent equation. Can you find one?
For part (b), the circuit to the left of the switch is disconnected so you can disregard it for any \$t>0\$.
The key insight for (b) is that the circuit is once again in DC steady state (all transients decay as \$t \rightarrow \infty\$).
Thus, the voltage across the inductor is \$0V\$, i.e., it can be replaced with an ideal wire.
Now, this leaves a simple current divider circuit so the inductor current is given by current division.
Best Answer
I would say that both answers are wrong. Imagine if the inductor were omitted from the circuit and any source of voltage or current were applied (via the 3 ohm series resistor) to what is basically a balanced bridge.
What would be the voltage at the junction of the two 1 ohm resistors - it would be the same voltage as at the junction of the two 3 ohm resistors - net voltage across the two points (where the inductor was connected) is always zero.
So, now replace the inductor and ask yourself what the net voltage across the inductor will be - it'll still be zero and never, ever will any current flow thru it.