Hi, let's there!
6x^4 -5x^2 + 12x^2 -10
Rewriting this equation as:
6x^4 + 12x^2 -5x^2 - 10
Now putting 6x^2 as commun factor
6x^2.( x^2 +2) -5x^2-10
Now putting -5 as commun factor
6x^2.( x^2 + 2) -5.( x^2 +2)
Now putting (x^2+2) as commun factor
(x^2 + 2).( 6x^2 +2)
Now putting 2 as commun factor on the expression 6x^2 +2
6x^2+2 = 2.( 3x^2 +1)
Then stay:
2.( x^2 +2).( 3x^2 +1)