SOLUTION: find the roots of the polynomial equation:x^3-2x^2+10x+136=0

Question 557276: find the roots of the polynomial equation:x^3-2x^2+10x+136=0

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
find the roots of the polynomial equation:x^3-2x^2+10x+136=0
-----
---
I graph the cubic and found a zero at x = -4
----
Using synthetic division, find the other zeros:
-4)....1....-2....10....136
........1....-6....34...|..0
----
Quotient: x^2-6x+34
---
Find the zeros of the quotient:
x = [6 +- sqrt(6^2-4*34)]/2
---
x = [6 +- sqrt(36-136)]/2
---
x = [6 +- sqrt(-100)]/2
---
x = [2 +- 5i]
x = 2+5i or x = 2 - 5i or -4
===================================
Cheers,
Stan H.
===================
RELATED QUESTIONS
Use the Rational Root Theorem to find all the roots of each equation. 4. x'3 +... (answered by stanbon)

Find the roots of the polynomial equation 2x^3 -4x^2 +2x... (answered by natolino_2017)

Find all zeros of the polynomial equation x3-2x2+10x+136=0 (answered by stanbon)

find the roots of the polynomial equation... (answered by stanbon)

Find the roots of the polynomial equation x^3 + x^2 -17x +15 =... (answered by Alan3354,Edwin McCravy)

Find all roots of the polynomial f(x) = x^4 - 5x^3 + 5x^2 + 17x - 42 + 4x^4 + 10x^3 -... (answered by CPhill,mccravyedwin,ikleyn)

Find the roots of the polynomial equation: x^3 � 3x^2 + 9x � 7 = 0 (answered by tommyt3rd)

Verify that -2 is a root of the equation {{{2x^3+x^2-10x-8=0}}} Find the other two... (answered by drk,richwmiller)

Find all roots of the polynomial f(x) = 3x^3 - 7x^2 - 10x + 4 + 4x^3 - 5x^2 + 18x + 28. (answered by CPhill)