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If `(x)/((x+2)(x+3))=(A)/(x+3)+(B)/(x+2)`, then `A-B` is `=`_________.A. `4`B. `5`C. `-6`D. `2`

Answer» Let `(x)/((x+2)(x+3))=(A)/(x+3)+(B)/(x+2)`
`(x)/((x+2)(x+3))=(A(x+2)+B(x+3))/((x+2)(x+3))`.
Consider `A(x+2)+B(x+3)=x`
Put `x=-3`, `-A=-3impliesA=3`
Put `x=-2`, `B=-2`
`:. A-B=3-(-2)=3+2=5`.


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