It's important to do so because you want to be sure it looks professional, just like it's important to add a cover to a report. It's also the first look at the resume and gives the overall look of it. It lets the job or employer know the specifics and into the resume talk more of what you do. It's like the overall information page..... Hope this helps.
The answer is 2 frequencies.
A Full-Duplex QAM 64 K Modem uses two frequencies. One frequency is used for upstream and the other for downstream. A variety of common QAM forms are available and include, 16 QAM, 32 QAM, 64 QAM, and 256 QAM. For example, for domestic broadcast use, 64 and 256 QAM are used for cable modem and digital cable TV. The modulation scheme for this modem uses both amplitude and phase.
Let's say for example that the business is taking in $2000 of revenue. That is the amount that the business collected for it's services - like for fixing the computer. What if though it costs $500 for the equipment (that's an expense). Now they only made $1500. Now the customer complains and says that the computer isn't fixed properly so the company sends out a techie for 2 additional hours. They need to pay their employee (another expense). Now the $1500 is down to $1400. They would have utilities to keep their lights on and insurance and many other expenses.
Your profit looks like this:
Profit = Revenue - Expenses
They all have ads. Some have inappropriate ads while some have irrelevant ads with respect to the website your on.