Answer:
[tex]12ab^2+2a^2b^2+10b^2[/tex]
Step-by-step explanation:
[tex]3ab(4b-ab) + 5b^2(a^2 + 2)\\\\\mathrm{Expand}\:3ab\left(4b-ab\right):\quad 12ab^2-3a^2b^2\\\\=12ab^2-3a^2b^2+5b^2\left(a^2+2\right)\\\\\mathrm{Expand}\:5b^2\left(a^2+2\right):\quad 5a^2b^2+10b^2\\\\=12ab^2-3a^2b^2+5a^2b^2+10b^2\\\\\mathrm{Add\:similar\:elements:}\:-3a^2b^2+5a^2b^2=2a^2b^2\\\\=12ab^2+2a^2b^2+10b^2[/tex]
