how many phone numbers are possible in the (404) area code if the seven digit number have the form FGH- where F is restricted to 3-9 and X, G and H can be any digit 0-9?

900 phone numbers possible.

Step-by-step explanation:

Given the seven digit numbers are of the form:

FGH-XXXX

Possibilities for F = 3 - 9 and X i.e. 9 possibilities

Possibilities for G = 0 - 9 i.e. 10 digits

Possibilities for H = 0 - 9 i.e. 10 digits

To find:

How many numbers are possible ?

Solution:

This problem is nothing but a problem in which we have to find out how many numbers are possible where each digit has a few options available.

Number of ways to select F = 8 digits from 3 to 9 and 1 alphabet X = 9

Number of ways to select G = 10 digits from 0 to 9

Number of ways to select H = 10 digits from 0 to 9

XXXX part will be same in all the numbers.

So, total phone numbers possible =

Hence, the answer is:

900 phone numbers possible.

98 points djdjsi zisksis sjsjsi sisksj sksjdj sksks sjsisj

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)