Answer the following questions about the equation below x^3 - 6x - 4 = 0 (a) Lis
ID: 3143749 • Letter: A
Question
Answer the following questions about the equation below x^3 - 6x - 4 = 0 (a) List all rational roots that are possible according to the Rational Zero Theorem. A. plusminus 4 B. -1, -2, -4 C. plusminus 1 D. plusminus 1, plusminus 2, plusminus 4 (b) Use synthetic division to test several possible rational roots in order to identify one actual root. One rational root of the given equation is -2. (Simplify your answer.) (c) Use the root from part (b) to solve the equation. The solution set is (Simplify your answer type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the answers as needed.)Explanation / Answer
x3 - 6x - 4 = 0
The constant term is -4.
Factors of -4 are 1,2,4,-1,-2,-4.
According to zero remainder theorem, these are the possible rational roots.
Of these -2 satisfies the equation.
We have
(x+2) | (x3 - 6x - 4) | x2 - 2x - 2
x3 + 2x2
------------------
-2x2 - 6x - 4
-2x2 + 4x
-------------------
-2x - 4
-2x - 4
--------------------
0
The quotient is x2 - 2x - 2
By formula the roots are [2 + (4+8)]/2 and [2 + (4+8)]/2
i.e 1 + 3 and 1 - 3.
The solution set is -2, 1 + 3 and 1 - 3