What is the general form for a number written in scientific notation? what are its practical applications?

The general form for a number written in scientific notation would be a x 10^n.  where a must be between 1 and 10, and n must be an integer. This type of form is useful when dealing with very large numbers or very small numbers. Hope this answers the question. Have a nice day.

2(4+x)

Step-by-step explanation:

"Twice the sum of" tells us it will be the equation times two

"the sum of four and a number" is easy, thats 4 + x

The second number is x because the number is not specified so we need a place holder, x in this case, to tell us that the number is not given.

All this put together = twice the sum of four and a number, or 2(4+x)