In accordance with the function <em>velocity</em>, the car will have a complete stop after 6 seconds.
<h3>When does the car stop?</h3>
Herein we have a function of the velocity of a car (v), in feet per second, in terms of time (t), in seconds. The car stops for t > 0 and v = 0, then we have the following expression:
0.5 · t² - 10.5 · t + 45 = 0
t² - 21 · t + 90 = 0
By the <em>quadratic</em> formula we get the following two roots: t₁ = 15, t₂ = 6. The <em>stopping</em> time is the <em>least</em> root of the <em>quadratic</em> equation, that is, the car will have a complete stop after 6 seconds.
To learn more on quadratic equations: brainly.com/question/2263981
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