Boe bot code help

Suppose we have those function already
void leftMotorRPM( int RPM)
void rightMotorRPM(int RPM)

how can make the boe bot forward , pivot left

void Forward(int Dist, int Speed)

void PivotLeft( int Angle, int Speed);

how can make the boe bot forward

Can you envision what the motors have to do to make this happen? Of course, moving forward is one thing. Moving forward at a specific speed is another. Moving forward at a specific speed, to move a specific distance is still another.
That last one is not possible without some feedback. How would you know how much wheel slippage (or wear) has occurred?

pivot left

Similar question. Turning left is simply a matter of making one motor turn faster than the other. The speed differential defines the radius of the turn. A negative ratio means that the device turns on a radius less than its length.
Turning through a specific angle requires feedback. You can't just make one side run faster for some fixed period of time and expect the robot to turn some specific angle.
When is our homework due?