Re-express −18−−−−√ as a complex number with the imaginary unit i=−1−−−√ .(1 point)

To express -√18 as a complex number with the imaginary unit i, we rewrite it as -√(9*2).

Taking the square root of 9, we have -√9 * √2.

Since √9 = 3, we can rewrite the expression as -3√2.

Now we can express -3√2 as a complex number by multiplying it by i:

-3√2 * i = -3i√2.

Therefore, -√18 can be expressed as -3i√2.