why in math, whenever you do an explanation, for example, 2x - 20, the subtraction sign make the 20 a negative number?

The negative sign is put before numbers to make them negative, or make their signs the opposite of what the are.

You have a 20.

+ 20

You don't need to put the + there if there is nothing before it, but that is a positive 20.

If you put a negative in front of it;

- (+ 20) = - 20

If you have a negative in front of parenthesis;

50 - (2x - 20)

50 - 2x + 20

70 - 2x

yes because they have the same amount of green and blur marbles.

step-by-step explanation:

whole numbers.

step-by-step explanation:

we are given the average monthly rainfall (in millimeters) model r(m) for the years 1900-2009 as a function of the month number m.

as we can see m is taken for the number of months for years 1900-2009.

we know that number of months can't be a negative number or decimal number or a fraction.

so, the number of months could be only positive whole numbers.

therefore, whole numbers is more appropriate for the domain of r.