Does 0=0?

Consider two equations in the form y = mx + b, where m and b are real numbers.
After setting the equations equal to each other (in other words, m₁x + b₁ = m₂x + b₂), George solves and ends up with an answer of 0 = -3.
Why? How would the graphs of these two lines relate?
How would the graphs be different if he ended up with 0 = 0?
Explain.