Find the partial fraction decomposition of
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[tex]\dfrac1{x(x-1)}=\dfrac ax+\dfrac b{x-1}[/tex]
[tex]1=a(x-1)+bx[/tex]
If [tex]x=0[/tex], then
[tex]1=-a\implies a=-1[/tex]
If [tex]x=1[/tex], then
[tex]1=b[/tex]
So we have
[tex]\dfrac1{x(x-1)}=\dfrac1{x-1}-\dfrac1x[/tex]