"Positive sign" is to right, the "Negative sign" is to left. Same as up and down.
How far is gone when it is acceleration, multiply the acceleration and changing time.
Final velocity is the intial velocity plus the areas that go when it's acceleration, which is multiply the acceleration and changing time.
V(intial)+(t)a=V(final);
When at begining the speed is constant velocity, then suddenly change into acceleration which the speed is changing over time.
The final the displacement is the constant velocity times changing time add the sum of final velocity-initial velocity over 2 then times changing time.
The graph can help solve the problem how far is object gone.
Average acceleration is 1/2 times the sum of initial velocity plus final velocity.
The displacement when the speed is acceleration, is the changing time times the average velocity.