Are you sure that there are two variables in your expression ( and )? I think they want ...
I've got an expression: . How can I factorise it? All methods I know are based on finding one solution and simplifying the expression to (x-a)(...). But this one is always positive, no matter x, so it's not possible here. It's a polynomial of degree 4, so it must be possible to at least make it to the form How can I do that? (only real numbers, please)
Try look under Application to higher-degree equations.
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