Question

A particle's position on the x-axis is given by the function x= t^2+6.00t+ 3.00 , where t is in s.
Where is the particle when v(x)= 5.00m/s ?

Answer 1

take the first derivative of f(x) to get velocity.

v=2t+6

Now put v =5, and solve for t.

By the way, v is a function of t, not x.