Question

hi i was reading through the tutorials and havent really understood how to factor out a trinomial like
12x^4 - 5x^2y^2 - 2y^4

what would the 1st few steps be?

Do a substitution:

let v= x^2 and u= y^2

Now you have...

12v^2 - 5uv - 2u^2

(3v -2u)(4v+u) then go back and put the x and y back in...
(3x^2 -2y^2)(4x^2+y^2)

Notice the first paren is the difference between two squares, so it can be factored more..
(xsqrt3 -y sqrt2)(xsqrt3 +y sqrt2)(4x^2+y^2)