Particle Motion Times When the Particle is at Rest problem ! ! ! ! !

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In this video you will learn how to the times when a Particle is at rest.

A particle moves along the x-axis so that at time t ≥ 0 its position is given by x(t) = 2t^3 - 21t^2 + 72t - 53. At what time t is the particle at rest?
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