A snowmobile has an initial velocity of 3.0 m/s. if it accelerates at the rate of 0.50 m/s squared for 7.0 seconds, what will its final velocity be?

It's final velocity would be + 6.5 m/s. You would use the kinematic equation:

Vf = Vi + at, then plug in the numbers. Vf = 3 + (.5 x 7) ...5 x 7 = 3.5, then adding it to Vi, which is 3, would get you Vf = 6.5