Find tension given a and m

Of an object held up by a string
m = 2.37 kg
a = 3.70 m/s

I calculated and got 18.6 N, but apparently that's wrong. :(:(:(

Also there was another where m = 1.19, and a = (4.81 - 2.61) / 2.4
I got 13.6 N, but that's wrong too...
WHAT THE FREAK?!!

Please help :P

Don't forget gravity, = 9.8m/sec^2.
(9.8 + 3.7) = net 13.5m/sec^2.
(13.5 x 2.37) = tension of 31.995N. in string.

Second one, same problem. Gravity omitted.

You haven't defined the direction of the acceleration.
Assuming it's up, and that you're doing this experiment on the surface of the earth,

T = m*(g+a) = 2.37*(9.8+3.70) = 32 N; if the acceleration is down,
T = m*(g - a) = 14.457 N

Part 2:
a = .9167 m/s² (according to your formula)

T = 1.19(9.8 ± .9167) = 12.75 N, 10.57 N for up and down acceleration, respectively

2.37 kg • 3.70 m/s² = 8.77 Newtons.

1.19 kg • (4.81 - 2.61) / 2.4 m/s² = 1.09 Newtons.