f(x)=1/(1-x)(2+3x)
=a/(1-x)+b/(2+3x)
2a+b+(3a-b)x=1
b=3a,5a=1->a=1/5,b=3/5
=(1/5)1/(1-x)+(6/5)/(1+(3/2)x)
=Σ((1/5)+(6/5)(-3/2)^n)x^n