Question

E(X)=(2/x^2-4 +1/x^2-2x - 1/x^2+2x):2x+6/x^3-4x

Answer 1

E(x)=[(2/(x²-4) +1/(x²-2x) - 1/(x²+2x)]:(2x+6)/(x³-4x )=

=[(2/(x-2)(x+2) +1/x(x-2) - 1/x(x+2)] × x(x²-4)/2(x+3)=

=(2x+x+2-x+2)/x(x-2)(x+2)  × x(x-2)(x+2)/2(x+3)=

=(2x+4)/2(x+3)=

=2(x+2)/2(x+3)=

=(x+2)/(x+3)