Answer:
[tex]5a^2+12b^2-40b[/tex]
Step-by-step explanation:
First distribute the -4 to the 2b and -3b. This leaves you with [tex]5a^2-8b+12b(b+4)[/tex]
Now you can distribute the 12b to b and +4. This leaves you with [tex]5a^2-8b+12b^2+48b[/tex]
Now you can combine your like terms leaving you with [tex]5a^2+12b^2-40b[/tex].
