answer:
15 square root of 6i
explanation:
square root of -54 can be re written as square root of -1 and square root of +54, the square root of -1 is basically i, and then the square root of 54 can be written as 9*6 and square root of 9 is 3
3 * 5 (which was outside the square root (see image) = 15 and square root of 6 is left along with the i
