1.

Use the Factor Theorem to determine whether g(x) is a factor of p(x) in each of the following cases:(i) `p(x)=2x^3+x^2-2x-1,g(x)=x+1`(ii) `p(x)=x^3+3x^2+3x+1,g(x)=x+2`(iii) `p(x)=x^3+4x^2+x+6,g(x)=x-3`

Answer» From Factor theorem,
`(y-a)` is a factor of `P(y) if P(a) = 0.`

(i)`p(x) = 2x^3+x^2-2x-1 and g(x) = x+1`
For `g(x)` to be a factor of `p(x)`, `p(-1)` should be `0`.
`p(-1) = 2(-1)^3+(-1)^2-2(-1) -1 `
`=-2+1+2-1 =0`As, `p(-1)` is `0`, `(x+1)` is a factor of `p(x)`.

(ii) `p(x) = x^3+3x^2+3x+1 and g(x) = x+2`
For `g(x)` to be a factor of `p(x)`, `p(-2)` should be `0`.
`p(-2) = (-2)^3+3(-2)^2+3(-2)+1`
`=-8+12-6+1 = -1`
As, `p(-2)` is not equal to `0`, `(x+2)` is not a factor of `p(x)`.

(iii) `p(x) = x^3+4x^2+x+6 and g(x) = x-3`
For `g(x)` to be a factor of `p(x)`, `p(-3)` should be `0`.
`p(3) = (3)^3+4(3)^2+3+6`
`=27+36+3+6=72`
As, `p(3)` is not equal to `0`, `(x-3)` is not a factor of `p(x)`.



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