To log on to a certain computer account, the user must type in a 4-letter password. In such a password, no letter may be repeated, and only the lower case of a letter may be used. How many such 4-letter passwords are possible

 358800

Step-by-step explanation:

To create a four-letter password such that no letter are repeated and only lower cases are used;

For the first letter, we can choose any letter from A to Z = 26

We can choose any letter from A to Z except for the first letter for the second letter. = 25

We can choose any letter from A to Z except for the first & second letter for the third letter. = 24

We can choose any letter from A to Z except for the first, second & third letters for the fourth letter. = 23

SO;

No of ways in which 4-letter passwords are possible = 26 × 25 × 24 × 23

No of ways in which 4-letter passwords are possible =  358800

d. 8

step-by-step explanation:

the given radical expression is:

we can rewrite this as:

we express as square numbers to get;

the exponents will now cancel out to give.

the correct answer is d

d 600 because 15*10*2=300

300+300=600

step-by-step explanation: