Answer: C, 24n²+8mn
Explanation:
So because 4n is on the outside of the bracket, you have to times everything on the inside of the bracket by 4n.
So, you do:
4n×6n=24n² (4×6=24 and n×n=n²)
4n×2m=8mn (4×2=8 and n×m=mn)
Then you add 24n² to 8mn like this:
24n²+8mn
Hope this helps :)