1.

Find the remainder when `x^999` is divided by `x^2-4x + 3`.

Answer» Let `q(x)` and mx + n be the quotient and the remainder respectively when `x^(999)` is divided by `x^(2)-4x+3`.
`:. x^(999)=(x^(2)-4x+3)q(x)+mx+n`.
If ` x= 1` , `x^(999)=(1-4+3)q(x)+m(1)+n`
`rArr1=0xxq(x)+m+n`
`rArrm+n=1` (1)
If ` x= 3`, `3^(999)=(3^(2)-4(3)+3)q(x)+3m+n`
`rArr3^(999)=0xxq(x)+3m+n`
`rArr3m+n=3^(999)` (2)
subtracting Eq . (1) from Eq . (2) , we get
`2m=3^(999)-1`
`m=(1)/(2)(3^(999)-1)`
Substituting m in Eq . (1) , we have
`n=1-(1)/(2)(3^(999)-1)=1-(1)/(2)3^(999)+(1)/(2)=(3)/(2)-(1)/(2)3^(999)`
`n=(3)/(2)(1-3^(999))`
`:.` The required remainder is `(1)/(2)(3^(999)-1)x+(3)/(2)(1-3^(999))`.


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