8. How many 6 digits telephone numbers are possible always starting from 562 (i) if the repetition of the digits is not allowed? (ii) if the repetition of the digits is allowed? 9. By using the digits from 0 to 9, how many three digit number can be constructed having only one zero given that the digits can be repeated?​

Step-by-step explanation:

For 3rd, 4th ,5th and 6th place, We have to choose digits from 0 to 9 but the digit 6 and 7 cannot be taken because repetition is not allowed. So, we have 8 possible digits for 3rd place. As repetition is not allowed, so we have 7 digits left for 4th place. Similarly, we have 6 digits and 5 digits left for 5th place and 6th place. The total number of 6 digit telephone numbers =8×7×6×5=56×30=1680

.

Therefore, total numbers =89×8×7504.

really really sorry if i'm

-12 -5(x + 4) = 3x

-12 - 5x - 20 = 3x

-12 - 20 - 5x = 3x

-32 - 5x = 3x

    + 5x   + 5x

-32 = 8x

8         8

- 4= x