Which expression is the factorization of x2 + 10x + 21? (x + 3)(x + 7) (x + 4)(x + 6) (x + 6)(x + 15) (x + 7)(x + 14)

First option.

Step-by-step explanation:

You need to remember that to factorize the given expression , you need to choose two numbers that when you add them you get "10" and when you multiply them you get "21".

These number are:

7 and 3

Because:

Therefore, you get that the factorization of the expression is the following:

You can observe that this factorization matches with the first option.

here

step-by-step explanation:

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)