1.

Resolve `(2x-5)/((x+2)(x^(2)-x+5))` into partial fractions.

Answer» Let `(2x-5)/((x+2)(x^(2)-x+5))=(A)/(x+2)+(Bx+C)/(x^(2)-x+5)`
`implies2x-5=A(x^(2)-x+5)+(Bx+C)(x+2)`………..`(1)`
Put `x=-2` in Eq. `(1)`
`implies-9=A(11)+0`
`A=(-9)/(11)`
Again put `x=0` in Eq. `(1)`, we have
`-5=5A+2C`
`-5=5xx(-9)/(11)+2C`
`impliesC=(-5)/(11)`
Comparing the coefficients of `x^(2)` on both sides of Eq. `(1)`, we have `A+B=0`
`B=-A=(9)/(11)`
`:.(2x-5)/((x+2)(x^(2)-x+5))=(-9)/(11(x+2))+((9)/(11)x-(5)/(11))/(x^(2)-x+5)=(1)/(11)[(9x-5)/(x^(2)-x+5)-(9)/(x+2)]`


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