Answer:
The answer is b
Step-by-step explanation:
If you do the square root button for both 729 is 27
and 862 is 29.36
4 x 9 = 36. Plug it back in to see if it is true: 36 / 9 = 4.
If Blake knows that one of the answers to x2, then the only correct answer there is is X equals four