It is 3i.
The square root of -9 is the square root of -1 times the square root of 9.
So: the square root of 9 is 3, and the square root of -1 is called i (this doesn't actually exist, it's just imaginary).
Then, the square root of -9 is 3i.
Hello :
14 = 2×7
21 = 3×7
<span> the least common denominator for the fractions 9/14and 2\21 is : 6×7=42</span>
I think it's A. I can't really see the graphs clearly. It's the one that crosses at (15,2)