5!.4! is equivalent to:

2880

Step-by-step explanation:

The "." or · means multiplication.

"!" means multiplying every consecutive positive whole number starting from 1 until the number infront of the "!". It's called a factorial.

4! = 1·2·3·4 = 24         The factorial of 4

5! = 1·2·3·4·5 = 120     The factorial of 5

Substitute the values of the factorials, then multiply them to solve.

5! · 4!

= (1·2·3·4·5) · (1·2·3·4)  

= 120 · 24

= 2880        Answer

Therefore 5!·4! = 2880.

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

-2 is the right