Are the three resistors that I circled in the paint doc in parallel??
It's fairly obvious that the top resistor is in parallel with whatever is going on below, right? So I suspect the bottom portion is giving you trouble.
Remember, the definition of components being in parallel means that current has the option of flowing through either component while being in series means that current must flow through both components. When the current travels through the bottom 2-resistor branch, is there more than one way to get past that part of the circuit?
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