The square of 9 less than a number is 3 less than the number. what is the number? –12 or 7 –12 or –7 –7 or 12 7 or 12

D:  7 or 12.

Step-by-step explanation:

Given statement "The square of 9 less than a number is 3 less than the number."

Let us assume unknown number is = n

9 less than a number = (n-9)

Square of 9 less than a number =

3 less than the number = n-3.

Therefore, we can setup an equation

Let us expand and now foil.

Therefore,

Adding 3 and subtracting n from both sides, we get

Factoring quadratic

n(n-12) -7(n-12) =0

(n-12)(n-7) =0

Applying zero product rule, we get

n-12=0    => n=12 or

n-7=0     => n= 7.

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