Two cars, a and b travel in a straight line along the x-direction along two different tracks. the displacement of the cars as a function of time are given by xa(t) = 4t + 2t² xb(t) = 5t − 2t³ and their velocities are given by: va(t) = 4 + 4t vb(t) = 5 − 6t² determine when the two cars will be in the same position. determine when the two cars will have the same velocity.