The piecewise function is basically the result of two different functions combined together. If x is 0 or larger, then h(x) = x+4. Otherwise, if x < 0, then h(x) = -x-4
No matter what number you pick for x, the h(x) function will be used in some way. So the domain is the set of all real numbers. To write this in interval notation, we write 
which means we start off at negative infinity and go to positive infinity. This is basically saying "the entire real number line". Since we can't actually reach either infinity, we always use parenthesis with them. <u>Never</u> use square brackets with either infinity
From the graph (see attached image below), we see that (0,-4) is the lowest point. This means y = -4 is the smallest y output possible, though we can't actually reach it because of the open circle at (0,-4). We can get any other larger y value. So the range is therefore: 
meaning we start at -4 and head off to positive infinity. The curve parenthesis next to -4 the reader "exclude -4 as part of the range". There is an open hole or gap here. Another way to state the range is to write y > -4
Multiply 18 * 3 and 20 * 3
18*3 = 54
20 * 3 = 60
Length = 54 cm ; Width = 60 cm
Area = L x W
54 * 60 = 3240
Area = 3240 cm
It depend on where you are working at that isn't a specific question
