Start with
[tex] 24x^3y^2+8xy [/tex]
As for the numeric part, notice that 24 is a multiple of 8, so we can factor 8 out of both terms:
[tex] 24x^3y^2+8xy = 8(3x^3y^2+xy) [/tex]
Now, both [tex] x [/tex] and [tex] y [/tex] appear in both terms. We can factor them out:
[tex] 8(3x^3y^2+xy) = 8xy(3x^2y+1)[/tex]