In the figure 2.13, the i1 and 7 A current flow in downwards in the branch. The i3 current flows up.
So the equation is written as
But if we think in such a way that i1 flows downwards, 7A flows downwards, i3 flows upwards,
then by kirchoff current law, i1+7=i3.So i1-i3 = -7
why is my thinking wrong.