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.
The Answer should be either x=15 or x=5 I got both.
Complementary angles add up to 90°
∠BDC + ∠CDA = 90°
Answer: ∠BDC
Answer:4
Step-by-step explanation: