How do you factor #2x^4-2x^2-40#?
Factor out a
Now, to make this look more familiar, say that
Which can be factorized as follows:
You change the variable, and the result is
This is quite a remarkable polynomial here, it only has even powers! So we can change the variable, let's say
So we now have to factorise
So finally, you can factorize it as