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If `(4x^(2)+5x+6)/(x^(2)(x+3))=(A)/(x)+(B)/(x^(2))+(C )/(x+3)`, then `2A+3B+4C=` __________.A. `10`B. `20`C. `30`D. `40` |
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Answer» `(4x^(2)+5x+6)/(x^(2)(x+3))=(A)/(x)+(B)/(x^(2))+(C )/(x+3)` `(4x^(2)+5x+6)/(x^(2)(x+3))=(Ax(x+3)+B(x+3)+Cx^(2))/(x^(2)(x+3))` Consider, `4x^(2)+5x+6=Ax(x+3)+B(x+3)+cx^(2)` Put `x=0`, `6=3BimpliesB=2` Put `x=-3`, `27=9CimpliesC=3` Comparing the coefficient of `x^(2)`, we have `A+C=4impliesA=1` `2A+3B+4C=2+6+12=20`. |
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