Answer:
Step-by-step explanation:
Being able to do this requires that you understand what is being asked and that you understand domain. This is a piecewise function, made up of 4 different parts, and each part has a domain different from every other part. Now look at the solutions. We are given coordinates, x and y. So this is how this problem is done.
In a. the coordinate is (-1, 1), right? x = -1 here, so the equation that we "pick" (I'll explain that in a sec) has to have a domain where -1 will fall. The first part of this piecewise has a domain of less than or equal to -11. Is -1 less than or equal to -11? No, it is not. -1 is greater than -11, so the equation we "pick" to use will not be this one. Look at the next piece of the function and note its domain. This domain is that x is greater than -11 and less than 5. Does -1 fit in that domain? Is -1 included in that spread of numbers? Yes it is, so that is the equation we will use. By use I mean that we will plug in -1 for x and see if y = 1 (that number comes from the coordinate (-1, 1) where y = 1). The equation is y = x + 2 and plugging in -1 for x:
y = -1 + 2 so
y = 1 and this point is on the piecewise. Let's do one more example so you can see how it looks when it DOESN'T work out, ok?
Look at b. The coordinate is (-2, -10). x = -2, so the same domain, same equation: x + 2. We plug in -2 for x to find y:
y = -2 + 2 so
y = 0. 0 does not equal -10, so this point is not on that graph.
The key here is picking the equation whose domain includes your x value and evaluating the equation at that value of x to find y.
