SOLUTION: Okay, so I tried doing this problem numerous times and didn't know what to do. -Find All Roots. x^3-13x^2+56x-78 Please And Thank you for your help (:

Question 193425: Okay, so I tried doing this problem numerous times and didn't know what to do.
-Find All Roots.
x^3-13x^2+56x-78

Please And Thank you for your help (:
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
-Find All Roots.
x^3-13x^2+56x-78
-------------
The only real root is 3.
Divide by (x-3) -->
x^2 - 10x + 26 = 0
Use the quadratic eqn to find the other 2 zeroes.
---------

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

The discriminant -4 is less than zero. That means that there are no solutions among real numbers.

If you are a student of advanced school algebra and are aware about imaginary numbers, read on.

In the field of imaginary numbers, the square root of -4 is + or - .

The solution is , or
Here's your graph:

----------
x = 5+i
x = 5-i

RELATED QUESTIONS
Please show me how to work out this problem. I know the roots are -1/3, -1/2, and 3, but (answered by Edwin McCravy)

Hi. I really need help with the factoring trinomial problem 1/2x(x+20)=78. I've tried to... (answered by faceoff57)

Okay, here goes another easy one that I can't solve: Printer A can print a report in 3... (answered by amnd)

Okay, so i am doing exponential functions. i do not get how to do it. how would i do this (answered by richwmiller)

I have no clue on what to do in order to solve this problem. I have tried numerous times... (answered by solver91311,lwsshak3)

Okay so I'm doing the factoring of trinomials when you have a coeffcient and your x is... (answered by richwmiller)

Hi could you please explain how to use substitution through this problem? I have tried... (answered by rfer)

How do you solve this system of equations using substitution (not elimination): 5x - 9y = (answered by ReadingBoosters)

i have tried so hard to figure out this problem but it seems so difficult. Given the... (answered by stanbon,solver91311)