Suppose that an object moves along the $y$-axis so that its location is $y = {-5}x^2 - 5x$ at time $x$. (Here $y$ is in feet and $x$ is in seconds.) Find the velocity (include units) of the object at each of following times:

(A) Velocity at $x = 3$ seconds:

(B) Velocity at $x = 6$ seconds:

(C) Velocity at $x = 8$ seconds:

You may want to consult the list of abbreviations of units known to WeBWorK.