The firstfour terms of (1 + m)6 are 1 + 6m + 6*5/2*m2 + 6*5*4/(3*2)*m3
So if m = x/3
a = 6/3 = 2
b = 6*5/2*(1/32) = 30/18 = 5/3
c = 6*5*4/(3*2)*(1/33) = 20/27
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