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This equation of the degree 4 is VERY SPECIAL.
It relates to the class of so named palindromic equations of the degree 4, which means that its coefficients
form a palindromic sequence.
See this Wikipedia article https://en.wikipedia.org/wiki/Reciprocal_polynomial#Palindromic_polynomial
There is a SPECIAL PROCEDURE in algebra to solve such equations. It is presented below.
= 0 (1)
It follows from the equation that x= 0 IS NOT the root.
So, we can divide both sides by without loosing the roots. In this way, you will get an equivalent equation
= 0.
Group and re-write it equivalently in the form
- + 50 = 0, or
- + 50 = 0. (2)
Introduce new variable u = + . Then equation (2) takes a form
= 0.
Solve this quadratic equation using the quadratic formula
= = .
The two roots are
= = = = and
= = = = .
Now, to find x, we need to solve two equations
a) + = and b) + = .
Case a). + =
= 0
= = = .
So, the two roots are = = 3 and = = .
Case b). + =
= 0
= = = .
So, the two roots are = = 2 and = = .
ANSWER. The four roots are , , 2 and 3.
Solved.
The lesson to learn
From this post learn on how to solve palindromic equations.
Every palindromic equation of the degree 4 can be solved in this way.
The major steps of the solution are :
a) Divide both sides by ;
b) Introduce new variable u = x + ;
c) Reduce the equation to a quadratic equation relative new variable u and solve it getting two roots and ;
d) Then find x by solving two equations = and = .
Again :
Every palindromic equation of the degree 4 can be solved in this way.