Simplify the rational expression. State any restrictions on the variable.
x^4+x^2-56/x^4-13x^2+42

Question

Simplify the rational expression. State any restrictions on the variable.
x^4+x^2-56/x^4-13x^2+42

anonymous · Answer

$$x^4+x^2-56/x^4-13x^2+42$$ Is it ok?

anonymous · Answer

Yes

anonymous · Answer

I guess is it not trivial. Did you learn a method to knowing a polinomi of 4th grade roots?

anonymous · Answer

Uhh what ?

anonymous · Answer

Did you learn a method to find roots?

anonymous · Answer

I probably did but I don't know what it's called...

anonymous · Answer

You have to do a variable change.

anonymous · Answer

Define a new variable  $$x' = x ^{2}$$ and then rewrite it. Would you do it?

jhonyy9 · Answer

so if you will note x^2 =t so than will get one equation in t like this 

t^2 +t-56
------------ = 
t^2-13t+42

so can you continue ? if you check thes equations well you can see that can fectorizing easy 

can you do it ?