how do i find at what negative time and positive time does the particle pass throught 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)
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