Simplify this expression.

3x2(7x2 - 9)

a.
21x2 - 9
b.
21x2 - 27x2
c.
21x4 - 9
d.
21x4 - 27x2

Option D is correct.

Step-by-step explanation:

In order to simplify the given expression we should know what Distributive property of number is.

It is given by  a*x (b-c )  = axb -axc

that is if a is outside of the parenthesis then a is multiplied to all the term inside one by one

here in the question outside is and inside is   and 9.

therefore   is multiplied to both    and 9

 So first term is obtained by  multiplying   by   which gives

and second term is obtained by multiplying   by 9 we get

So expression is   -

answer: 80,000

step-by-step explanation:

the population doubles every day.

10,000*2=20,000 day 4

20,000*2=40,000 day 5

40,000*2=80,000 day 6