def nest(x, a):
nested = 0
for i in range(0, len(a)):
nested = nested * x + a[i]
return nested
a = [6,1,5,1,1]
b = [-3,4,5,-5,1]
c = [2,1,-1,0,1]
print(nest((1/3),a))
print(nest((1/3),b))
print(nest((1/3),c))
fa(x) = 6*x^4 + x^3 +5*x^2+x+1
fb(x) = -3*x^4+4*x^3+5*x^2-5*x+1
fc(x) = 2*x^4+x^3-x^2+1
print(fa(1/3))
print(fb(1/3))
print(fc(1/3))