Since the square root of 9 is 3, we can simplify this as -√9 = -3. That's a negative integer. It also counts as a rational number and a real number.
Example 2
If x2 = -4, is x a real or imaginary number?
Answer
It's imaginary. To get x by itself, we need to take the square root of both sides. But the square root of -4 is 2i, which is imaginary. Check it out: (2i)2 = (22)(i2) = 4i2 = 4(-1) = -4.