Negative time and positive time

[kellyab8]

how do i find at what negative time and positive time does the particle pass through the origin?

 

[rock.freak667]

how do i find at what negative time and positive time does the particle pass through the origin?

At the origin x=0 and t=0. It seems you want to find when x=0, ( I assume x=displacement)

So just put 4.0-6.0t²=0 , then make t² the subject and take the square root of that number. You're answer will then be t=±√(number)