a)f(x)=x^7
f(-x) = (-x)^7 = (-1)^7*x^7 = -x^7 = -f(x) --> punktsymmetrisch
b)f(x)=x^6
f(-x) = (-x)^6 = (-1)^6*x^6 = x^6 = f(x) --> achsensymmetrisch
c)f(x)=3x^9
f(-x) = 3*(-x)^9 = 3*(-1)^9*x^9 = -3x^9 = -f(x) --> punktsymmetrisch
d)f(x)=x^5+1
f(-x) = (-x)^5 + 1 = -x^5 + 1 --> keine Symmetrie
e)f(x)=x^5+2x
f(-x) = (-x)^5 + 2*(-x) = -x^5 - 2x = -(x^5 + 2x) = -f(x) --> punktsymmetrisch