SOLUTION: How do I find the real zeros to the problem f(x)= x^4+x^3-8x^2-9x-9?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: How do I find the real zeros to the problem f(x)= x^4+x^3-8x^2-9x-9?      Log On


   

Question 926867: How do I find the real zeros to the problem f(x)= x^4+x^3-8x^2-9x-9?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

f(x)= x^4+x^3-8x^2-9x-9, x = ± 3 are roots (81+27-72-27-9) = 0 And( (81-27-72+ 27-9)= 0

Using Synthetic Division

3	1	1	-8	-9	-9

		3	12	12	9

	1	4	4	-3	0  and again

-3		-3	-3	3	

	1	1	1	0	

(x-3)(x+3)(x^2 + x + 1)

.......

x^2 + x + 1  has imaginary roots

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ 

x+=+%281+%2B-+i%2Asqrt%28+3+%29%29%2F2+ 

-.5 ± .5i√3