Finding particle position at t = 2.70 s and t = 2.70 s + Δt for x = 6t²

[GlobalDuty]

Homework Statement

The position of a particle moving along the x-axis varies in time according to the expression
x = 6t^2, where x is in meters and t is in seconds. Evaluate its position at the following times.
(a) t = 2.70 s

(b) t = 2.70 s + Δt
xf =

Homework Equations

(Use Deltat for Δt.)

The Attempt at a Solution

I understand that for part A, all i do is plug in (2.70) into 6(2.70)^2 to get the answer.
But what do i do for part b with that "Δt"?? and the answer for part b is supposed to be in symbolic format

 

[rl.bhat]

dx = 12*t*dt
And xf = x + dx.