Thanks I get how to do it but want to make sure I did it right can you please check? Here is what I did:

(4x^2-9)-11(4x^2-9)+24=0

Let w=(4x^2-9)

w^2-11w+24=0

factored to become (w-8)(w-3)=0

sub in w value (4x^2-9-8)(4x^2-9-3)=0

(4x^2-17) (4x^2-12)=0

so solving for x

4x^2-17=0

4x^2=17

x=the square root of +or- 17/4

or 4x^2-12=0

4x^2=12

x=the square root of +or-3