i really need help on this problem!!

Three blocks are connected,on a horizontal frictionless table and pulled to the right with a force T3 = 64.4 N. Assume that m1 = 12.5 kg, m2 = 25.0 kg, and m3 = 31.7 kg. (a) Calculate the acceleration of the system (b)Calculate the tensions T1 and T2 in the interconnecting cords.

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