If $\frac{x^2-3x+1}{(x-1)(x-2)(x-3)}=\frac{A}{x-3}+\frac{B}{(x-1)(x-2)}+\frac{C}{(x-1)(x-2)(x-3)}$,then $B=$

The partial fraction of $\frac{3x - 1}{(1 - x + x^2)(2 + x)}$ is:

If $\frac{3 x^4+5 x^2+2}{\left(x^2+1\right)^2\left(x^2+2\right)}=\frac{A x+B}{x^2+2}+\frac{C x+D}{x^2+1}+\frac{E x+F}{\left(x^2+1\right)^2}$,then $A+2 B+D+4 E=$

If $\frac{1}{(x-1)(x-2)(x-3)}=\frac{A}{x-1}+\frac{B}{x-2}+\frac{C}{x-3}$ and $\frac{x}{(x-1)(x-2)(x-3)}=\frac{P}{x-1}+\frac{Q}{x-2}+\frac{R}{x-3}$, then $A+2B+3C=$

The partial fraction of $\frac{x^2 - 5}{x^2 - 3x + 2}$ is:

If $\frac{x^4-6 x^3+9 x^2+5 x-20}{x^2-x-2}=f(x)+\frac{a}{x+p}+\frac{b}{x+q}$,then $2(a+b)=$