Question

PLEASE HELP QUICK Suppose a particle is moving along the x-axis. The position, measured in feet, of the particle can be modeled by the quadratic equation y = 3x2 − 12x − 9, where x is time, in seconds. What does the number −9 represent for the quadratic function? The particle is 9 feet to the left of the origin. The particle is moving left 9 feet per second. The particle is accelerating at −9 feet per second squared. The particle has stopped at 9 seconds.

Answer 1

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.