Final answer:
The correct option is a.
When y=6 and dy/dt=8 for a particle moving on the hyperbola xy=18, the value of x can be determined by rearranging the equation to x = 18/y, yielding x = 3.
Step-by-step explanation:
To find the value of x when y = 6 and dy/dt = 8 for a particle moving on the hyperbola defined by the equation xy = 18, you can simply rearrange the equation to solve for x.
Multiply both sides of the equation by y, then divide both sides by y:
xy = 18 → x = 18/y
Substitute y = 6 into the equation:
x = 18/6
x = 3
Therefore, the correct answer is a. x = 3.