Step-by-step explanation:
Hey there!!
Here,
Initial velocity (u) = 6m/s.
Acceleration (a) = 1.7m/s^2.
Time (t) = 4.2s.
final velocity (v) = ?
We have,

Putting their values,

7.14 = v - 6
v = 7.14 + 6
Therefore, the final velocity is 13.14 m/s.
Hope it helps....