Question

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

Answer 1

\[x^4+x^2-56/x^4-13x^2+42\] Is it ok?

Answer 2

Yes

Answer 3

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

Answer 4

Uhh what ?

Answer 5

Did you learn a method to find roots?

Answer 6

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

Answer 7

You have to do a variable change.

Answer 8

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

Answer 9

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 ?