Define the proper and improper subsets?

A proper subset is one that contains few elements of the original set whereas an improper subset, contains every element of the original set along with the null set.

x = ± 6i

step-by-step explanation:

x^2 = -36

take the square root of each side

sqrt(x^2) = sqrt(-36)

we know sqrt(ab) = sqrt(a) sqrt(b)

x = ±sqrt(36) sqrt(-1)

we know that sqrt (-1) = i

x = ± 6i