More Geometry Help...Please Explain?

Question

37 Which is a complet factorization of 6x^4 + 12x^2

A) x^2(6x^2+12)

B) 3x^2(2x^2 +4)

C) 6x^2(x^2 +2)

D) 12x^2(2x^2+1)

#44 How many ways can 4 people sit at a table with six seats?

a 15

b 24

c 120

d 360

#49 Simplify √40

A) √40

B)2√10

C)4√10

D) 5√8

#50 y varies inversely as x. x1= 5, y1=4, and y2=2. Find x2.

a 10

b 18

c 20

d 40

PLEASE EXPLAIN

THANK YOU :)

Answer 1

37) Each of the terms has a common factor of 6x^2.

44) The first person can sit at any of the 6 seats, the second can sit at any of the remaining 5, and so on.  To find the total combinations, you multiply all the possible choices of each person:

6*5*4*3 = 360

49) √40 = √(4*10) = √4 * √10 = 2√10

50) I'm gonna let you do this one... I've helped enough.