factorise-: x³-3x²-9x-5
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Answer:
(x+1)is a factor of x^3-3x^2-9x-5. Given equation is x^3 - 3x^2 - 9x - 5. x + 1 is the factor. = (x + 1) (x - 5) (x + 1).
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Step-by-step explanation:
Given :
A polynomial x^3 - 3x^2 - 9x - 5
To Find :
Three factors of polynomial x^3 - 3x^2 - 9x - 5
Solution :
Constant Term = -5
Factors of Constant Term = 1,5
Putting x = 1 :
→ (1)^3 - 3(1)^2 - 9(1) - 5
→ 1 - 3 - 9 - 5
→ 1 - 17
→ - 16
Putting x = -1 :
→ (-1)^3 - 3(-1)^2 -9(-1) - 5
→ - 1 - 3 + 9 - 5
→- 4 + 9 - 5
→5 - 5
→ 0
x = -1 is the root .
x + 1 is the factor.
(Refer to the attachment)
Now :
→ x^2 - 4x - 5
→ x^2 - (5x - 1x) - 5
→ x^2 - 5x + 1x - 5
→x(x - 5) + 1(x - 5)
→ (x + 1)(x - 5)
So , The three factors are (x+1) , (x-5) , (x+1)...
Attachments:
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