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Mathematics 10 Online
OpenStudy (horsegirl27):

1.Change the equation into slope-intercept form. Identify the slope and y-intercept of the equation. Be sure to show all of your work. 2.Describe how you would graph this line using the slope-intercept method. Be sure to write in complete sentences. 3.Write the equation in function notation. Explain what the graph of the function represents. Be sure to use complete sentences. 4.Graph the function using one of the following two options below. One the graph, make sure to label the intercepts

OpenStudy (horsegirl27):

I really need the answers soon to finish my homework. I am really confused by the explaining part in question 3

OpenStudy (anonymous):

Do you have an equation they gave you?

OpenStudy (horsegirl27):

let me check I think so

OpenStudy (horsegirl27):

2x + 3y = 1,200

OpenStudy (horsegirl27):

I already did the homework now(and somehow got a 100%) but I didn't understand what I was doing and wouldn't be able to do it on another question without help so I would like to know how to do it because it will be on my test.

OpenStudy (horsegirl27):

I have another question after this too.

OpenStudy (sleepyjess):

I am not sure about #3, but I could help on the rest

OpenStudy (horsegirl27):

ok

OpenStudy (sleepyjess):

Ok, so the equation is 2x + 3y = 1200. We need to make this look like y = mx + b

OpenStudy (horsegirl27):

ok

OpenStudy (sleepyjess):

Do you have any guesses on how to do that?

OpenStudy (sleepyjess):

First we need to move +2x to the right side

OpenStudy (sleepyjess):

Also, \({\huge\color{black}{\bigstar}\color{black}{\hspace{2pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{lblack}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{4pt}\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{6pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\hspace{1.5pt}\bigstar}\color{black}{\hspace{1.5pt}\bigstar}}{\hspace-318pt\huge\color{red}{\bigstar}\color{orange}{\hspace{2pt}\bigstar}\color{goldenrod}{\bigstar}\color{yellow}{\bigstar}\color{lightgreen}{\bigstar}\color{green}{\bigstar}\color{turquoise}{\bigstar}~\color{royalblue}{\hspace{4pt}\bigstar}\color{purple}{\bigstar}~\color{#00bfff}{\hspace{6pt}\bigstar}\color{#00bfff}{\bigstar}\color{#00bfff}{\bigstar}\color{#11c520}{\bigstar}\color{#11c520}{\hspace{1.5pt}\bigstar}\color{#11c520}{\hspace{1.5pt}\bigstar}}\\\huge\bf\color{black}W\color{black}E\color{black}{\hspace5ptL}\color{black}{\;C}\color{black}{\;O}\color{black}M\color{black}{\,E~\;}\color{black}{\hspace{4.2pt}T}\color{black}{\:O}~~\color{black}{\hspace{4pt}Open}\color{black}{Study}\hspace-318pt{\huge\bf\color{red}W\color{orange}E\color{goldenrod}{\hspace5ptL}\color{yellow}{\;C}\color{lightgreen}{\;O}\color{darkgreen}M\color{turquoise}{\,E~\;}\color{royalblue}{\hspace{4.2pt}T}\color{purple}{\:O}~~\color{#00bfff}{\hspace{4pt}Open}\color{#11c520}{Study}}\\\huge\color{black}{\bigstar}\color{black}{\hspace{2pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{5pt}\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{6pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\hspace1.5pt\bigstar}\color{black}{\hspace{1.5pt}\bigstar\hspace-318pt{\huge\color{red}{\bigstar}\color{orange}{\hspace{2pt}\bigstar}\color{goldenrod}{\bigstar}\color{yellow}{\bigstar}\color{lightgreen}{\bigstar}\color{green}{\bigstar}\color{turquoise}{\bigstar}~\color{royalblue}{\hspace{5pt}\bigstar}\color{purple}{\bigstar}~\color{#00bfff}{\hspace{6pt}\bigstar}\color{#00bfff}{\bigstar}\color{#00bfff}{\bigstar}\color{#11c520}{\bigstar}\color{#11c520}{\hspace1.5pt\bigstar}\color{#11c520}{\hspace{1.5pt}\bigstar}}}\\\small\cal Made~by~@sleepyjess\)

OpenStudy (horsegirl27):

thanks

OpenStudy (horsegirl27):

and I think you subtract -2x from each side

OpenStudy (sleepyjess):

Yep

OpenStudy (sleepyjess):

So once you subtract 2x, you get 3y = -2x + 1200

OpenStudy (horsegirl27):

yes what's next? I know the final answer but I don't understand the work

OpenStudy (sleepyjess):

Ok, now divide everything by 3 to isolate y

OpenStudy (horsegirl27):

ok so I get y=2/3x+400?

OpenStudy (sleepyjess):

Yes!

OpenStudy (sleepyjess):

That is how you get the answer for the first one.

OpenStudy (horsegirl27):

oh ok thx now I understand the work for that one

OpenStudy (sleepyjess):

Ok, now for the second one, we have to explain how to graph it

OpenStudy (sleepyjess):

There is a simple way and a hard way to graph, we will try the easy way first

OpenStudy (horsegirl27):

ok

OpenStudy (sleepyjess):

Now we have the equation \(\sf y~=~\dfrac{2}{3}x~+~400\). The simple way is to plug in any value for x, and come up with y. For example, if I plug in 1 for x: \(\sf y~=~\dfrac{2}{3}(1)~+~400\\\) \(\sf y~=~\dfrac{2}{3}~+~400\\\) \(\sf 400.\overline{666}\)

OpenStudy (sleepyjess):

We can tell from the slope that we have to go up 3 x values to get a whole number for y

OpenStudy (horsegirl27):

um ok

OpenStudy (sleepyjess):

Oh wait, do you know what the slope and y-intercept is?

OpenStudy (horsegirl27):

yes

OpenStudy (sleepyjess):

Ok, do you see how I am doing this?

OpenStudy (igreen):

Actually it would be y = -2/3x + 400

OpenStudy (igreen):

Not 2/3.. Because you originally had -2, and dividing 3, will give you -2/3..

OpenStudy (sleepyjess):

Oh whoops, thanks for catching that @iGreen

OpenStudy (igreen):

y = -2/3x + 400 answers your question for #1 It's in Slope Intercept form..now you have to say what the slope and y-intercept are..do you know what the slope and y-intercept are for this equation? @horsegirl27

OpenStudy (horsegirl27):

slope is -2/3and y-intercept is 400 I think

OpenStudy (igreen):

You got it! So that answers #1 for you.

OpenStudy (sleepyjess):

Yep! ^_^

OpenStudy (horsegirl27):

oh thank you!

OpenStudy (igreen):

Now for #2, we can say to plot the y-intercept, which we know as 400, then we draw a line with a slope of -2/3 through it.

OpenStudy (igreen):

For #3, writing an equation in function notation is just replacing 'y' with 'f(x)'. \(y = -\dfrac{2}{3} + 400\) So what do you get?

OpenStudy (horsegirl27):

ok and because rise over run the slope would be down 2 over 3 right? and it will go through 400 on the y-axis but what about on the x-axis?

OpenStudy (sleepyjess):

Yep, I think @iGreen has this one :)

OpenStudy (igreen):

Drawing the line will tell you everything..you don't need the x-axis.

OpenStudy (horsegirl27):

yes but thanks @sleepyjess for helping

OpenStudy (horsegirl27):

oh ok

OpenStudy (sleepyjess):

|dw:1420639659256:dw|

OpenStudy (igreen):

Yep! ^^

OpenStudy (horsegirl27):

and I got f(x)=2x+400. Or is it f(x)=-2/3x+400?

OpenStudy (sleepyjess):

Note: this is not the most accurate graph |dw:1420639770878:dw|

OpenStudy (sleepyjess):

All you do for function notation is replace y with f(x)

OpenStudy (sleepyjess):

Everything else stays the same

OpenStudy (horsegirl27):

so it's f(x)=-2/3x+400?

OpenStudy (sleepyjess):

Yes

OpenStudy (sleepyjess):

What are the 2 options for part 4?

OpenStudy (horsegirl27):

oh ok so not f(x)=2x+400

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