Answer:
28
Explanation:
784 can be divided by two 4 times.
This means that there are two pairs of 2s that can come out the radical.
2*2 = 4.
then now we have 49 left inside and we know that this is 7 squared, meaning that there is a pair of 7 inside the radical.
7 comes out and now we have 7 times 4 which is 28.