SOLUTION: Find the rational zeros of the polynomial. List any irrational zeros correct to two decimal places. f(x) = x^4 - x^3 - 7x^2 + 5x + 10

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Find the rational zeros of the polynomial. List any irrational zeros correct to two decimal places. f(x) = x^4 - x^3 - 7x^2 + 5x + 10       Log On


   

Question 928786: Find the rational zeros of the polynomial. List any irrational zeros correct to two decimal places.
f(x) = x^4 - x^3 - 7x^2 + 5x + 10
Answer by ewatrrr(24785) About Me  (Show Source):
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Hi

f(x) = x^4 - x^3 - 7x^2 + 5x + 10 

1 + 1 - 7 -5 + 10 = 0,  16-8-28+10+10 = 0

Using Synthetic Division (x = -1  and x = 2  are roots found by plug and play)

-1	1	-1	-7	5	10

		-1	2	5	-10

	1	-2	-5	10	0

2		2	0	-10	

	1	0	-5	0	

f(x) = (x+1)(x-2)(x^2 - 5)= 0

x = -1, 2, 2.24, - 2.24