How to Calculate Inductor Current iL(t) in an RL Circuit for a Given Time t

I don't know how to do this. If someone can help me it would be appreciated.

Hi,

Please review your circuit analysis. This is a DC circuit and its analysis is not quite difficult compares to AC.

The HyperPhysics website is a good place to start for basic problems like this. Take a look at: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html

How do I solve this?

I will lead you to the water, but ...

The problem is the opposite of the Hyperphysics analysis. at t=0, the current in the inductor is 3A. At t=infinity, the current in the inductor is the same as the current in the 5ohm resistor on the left (which can be calculated using node analysis). The curve can be generate from the hyperphysics analysis except that you have to invert the Y axis on the v/t and i/t curves on the chart (3-i instead of i).

I hope this is enough. I would be doing you a disservice by giving you the answer, if you are in an EE program it is critical that you can solve these types of problems because they form the foundation of significantly more difficult problems you will see in the future (the AC analysis commented on above).