Thevenin and Norton circuit analysis example

Question

I have trouble solving the following problem, I have to find the Thevenin and Norton equivalent at the head of the R5 resistor:

^{simulate this circuit – Schematic created using CircuitLab}

I have calculated successfully the equivalent resistance, I am having trouble finding Vth, I replaced R5 with an open circuit like this:

^{simulate this circuit}

But I don't get the expected result, I realize that this problem isn't necessarily difficult, but I find that there is something I am missing while trying to solve it and I would appreciate some help, thank you !

Answer 1

This is easy to solve:

You keep combining sources until you are left with a single source. In this case, working with Thevenin sources (as apposed to Norton) seems easier.

V1,R1 is a Thevenin source you can see by inspection. So is V2,R2. Combine them.

Now add R3 to the resistance of that source. That is the Thevenin equivalent looking left into the right side of R3.

Add R4 to this and force I4 thru the result.