Suppose that the username of myITU system must satisfy the following requirements: (i) each username must be eight to twelve characters long; (ii) each character in the username must be a letter (a-z or A-Z) or a digit (0−9); and (iii) each username must contain at least one digit (0−9). (iv) each username must start with a letter (a-z or A-Z). How many possible usernames are there for myITU system? Provide your argument to support your answer

browsing like internet search? don't look at anything stupid. or set up restrictions on ur device's search engine. and if something suspicious comes up don't be dumb and click on it. i hope that's what ur question meant.

we can all learn from our past mistakes because we all have different ways of learning different types of techniques. my way may or may not another classmate remember and have the repetition to acknowledge such standard. such as remembering acronyms. using abbreviations to us remember keep things in order in our memory. this us figure out what comes next in the sequence. if so, what we have is a sentence of just letters all in caps. we either know the meaning or have no idea what it stands for. most of the time we know the meaning and context. but most of us who don't know, should learn by having a quick glance at what needs to be remembered. such as repetition in the memory for acronyms. one way that me, is the fact that i'm always doing math and english assignments. so we have to remember specific meanings such as soapstone for documents, such as citing correctly. or pemdas for doing the equations correctly, even if it's the super long way. this works for everyone. you just have to find what works for you by practicing and repetition daily.