Question #1f2c9

1 Answer
Dec 11, 2017

a. Its really up to you but three possible pairs can be: #(2,3),(5,3),(10,3)#

b. Zero

c. (See Graph)

Explanation:

We can think of the equation/function of the line #y=3# to be #f(x)=3#. They mean the same exact thing but this notation of #f(x)# will help make sense of what I'm about to say next.

The notation #f(x)# basically means the value of the function f when evaluated at a number x.

So if I wanted to find the value of the function when #x=2# then I would simply substitute #2# for every #x# I see in the function:

Thus, #f(2)=3#

This is a very special case however which I will explain further in detail later but in English, this says, the value of the function when #x# is 2 is 3.

Interestingly this will be true for any value of #x#.

a. An ordered pair is a fancy way to say point. We are asked to find at least three points that satisfy the equation which is to say find three points on the graph of #y=3#

Remember how earlier I mentioned the notation #f(x)# basically means the value of the function f when evaluated at a number x. Another way to think about this is as an input and output relationship.

Similarly then, if I input #2# into the function, the output will be #3# by the same reasons of the first example and again, this will be true for any value of #x# in this particular case.

We can describe this input/output relationship graphically as an #(x,y)# coordinate.

Using the example above, I can thus translate #f(2)=3# to #(2,3)# which I can then plot on the graph.

We repeat this process for as many times as we want but remember that in this particular case, the output/value of the function will always be #3# so really any number will satisfy the equation.

So three coordinates/ordered pairs can be

#(2,3)#

#(5,3)#

#(10,3)#

But generally, #(x,3)# where #x# is any number.

b. The slope of #y=3# is the slope of a horizontal line which has a slope of ZERO and that is a given fact.

However, if you need to prove it then we can take two coordinates that we already found from above we can apply the slope formula:

#m=(y_2-y_1)/(x_2-x_1)#

Where one coordinate is denoted as #(x_1,y_1)# and the other #(x_2,y_2)#

By applying this formula, you should always get #0# as the slope no matter what two coordinates you choose.

c. Thinking generally, the line of #y=#anything is one that crosses the #y-#axis and is a horizontal line. There are multiple ways to graph this equation:

One way (and probably the easiest in this case) is to use the coordinates that you chose and plot them then draw a line through those lines. What you should end with is a straight horizontal line.

Another way to think about it is to look at the generally #y=mx+b# formula which the general equation of a line where #m# is the slope and #b# is the #y-#intercept. We have already established that the slope of this line is #0# and so looking at the equation #y=3#, it is really the equation #y=0x+3# which means the #y-#intercept is #3# Given that, we plot the #y-#intercept #(0,3)# and draw a horizontal line.

In the end the graph should look something like this:

graph{0x+3 [-5.136, 4.726, -0.157, 4.774]}