True, the dependent variable should be on the left. Sometimes it matters less, for example to express that two sides have the same length, a = b and b = a would both be acceptable.

Possibly more important, you would never see:

  a = 3
  a = 4

Begs the question: which is it, 3 or 4? Or does 3 = 4 too? Just a reminder that the operators really are equality, not assignment.