Kirchhoffs Law with 3 Voltage Sources
You should try something different, using meshes. I'll do the one on the left.

$$
+20-3I_l-30-3I_l=0
\implies I_l = -\frac{5}{3}\ A
$$

On a side note, this problem could be easily solved with superposition. If you know about it, then you might want to give it a shot.