Re: nodal voltages
Hai,
Apply Source transformation theorem.The 5A and 3ohms &2 ohms are converted into single voltage source 25V ( 5A*3+2) in series with 5ohms(3+2).But the positive terminal connected to ground pin.
Similarly 2A and 4ohms are converted into single voltage source 8V( 2A*4ohm) in series with 4 ohm resistor.Now connect 15 ohms in between.
apply KVL now the V1 is -18.125V and V2 is 2.5V.
If you still feel problem i send picture tomorrow. But please try your self this, i should not tell every thing.