never mind i finally got it, i kept trying to solve t2 in terms of t1 and substituting that and it became rediculously convoluted. Finally just subbed in 2t2 for t1 and was able to isolate so looks like a1=4.9 m/s^2, a2=9.8 m/s^2, a3=0 m/s^2, t1= 39.2N, t2= 19.6N, a'= 4.9 m/s^2