Hey guys, it wasn't a homework program, i'm currently reading "Basic electronics for Scientists and Engineers" and there was a problem in it related to that but I put different values on the schematic, I want to learn the method vs just the answer so I appreciate the help there. I found the thevenin method much easier to comprehend than the first method (kirchoff's current and voltage laws if I remember correctly?) so thank you for all the replies!

In reply to KrisBlueNz, I understand how to work out the voltage across R2 (9.09v)

So would my method be:

R1||R3 = (1/100 + 1/300)^-1

Then 10/R1||R3 = 7.5v @75ohm (as you stated)

To then work out the voltage across the 200ohm resistor:

R1||R3 in voltage divider with the 200ohm resistor

7.5v to -5v is equivalent to 12.5v to 0v

12.5*200/(200+75) = 9.09v

Now i've calculated the voltage across R2, the voltage at the node that all the resistors meet should be 9.09v-5v = 4.09v

Therefore current through R3 = 4.09/300 = 13.6mA

and current through R1 will be (10-4.09)/100 = 59.1mA

Is this correct?

Thanks a lot guys, really appreciate it