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.
