What is 2 times the difference between 49.5 and 37.5

When 'x' is zero, 'y' is -9.

That simply means that when time began ... when the starter

fired his pistol and the clock started running ... the particle

was 9 units 'before' zero, in the region of negative location.

By the way ... the way the question is written is enough to confuse

anyone, and I hope that hasn't contributed to your trouble with it.

If the particle is moving along the x-axis, then 'x' is its location,

and the time in seconds is something else. Say 't' for example.

Also, if it's moving along the x-axis, then 'y' is always zero.

The position of the particle is modeled by an equation like

X = 3t² - 12t - 9 .

'X' is the position of the particle, and 't' is the time in seconds.