Respuesta :
Answer:
[tex]9 \cdot 10^6[/tex]
Step-by-step explanation:
A phone number contains 7 digits. How many different numbers can be made using the digits 0–9 if the first digit is not 0 and all of the digits can be repeated
In 7 digit phone number, the first number cannot be 0
So only 1 to 9 are used to get the first digit. 9 numbers can be used
other digits can use number from 0 to 9. 10 number can be used
So possible numbers can be made is
[tex]9 \ times \ 10 \ times \ 10 \ times \ 10 \ times \ 10 \ times \ 10 \ times \ 10[/tex]
[tex]9 \cdot 10^6[/tex]
