Analysis in a motor controll amplifier circuit
The opamp, T1 and T2 are a voltage follower and, due to negative feedback and the massive open loop gain of the opamp, the voltage across R2 equals Vin. No need to delve into algebra to resolve this. This means that the current in the motor is Vin / R2.

No need to even consider what the Vbe of each transistor is. The opamp output drives enough voltage to overcome the Vbe volt drops and maintain equilibrium at its inputs. Of course, for this to work, the opamp positive supply voltage needs to be typically 2 to 4 volts higher than the maximum value for Vin. 

If you wanted to be a little more precise about things, the next consideration is that the current through R2 is actually motor current plus the base current and, if the beta of T2 is low you will have a significant error in the simple analysis. Normally you could expect less than a 5% error but, as you turn up Vin this may rise to 10% as beta drops towards 10.