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Video Notes 4.1, Day 1 of 2: Non-Proportional Relationships - - Math8

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I needed your video notes for Section 4.1 and Tren today worksheet with the problems for you so that we can focus on just doing the work all right so we have a word problem and the word problem live rezende non-proportional relationship so now we're diving into eighth grade math pre-algebra leading up to algebra so pay attention to that notice that it's a new section 4.1 make sure that you update your table of hunt senior notebooks as well right word problem says you have $100 to spend on lunch for the month the school lunches $4 show how much money you have left after X days you buy your lunch so I live with it for you ask is going to be there I mean that why has to be the money that you have left over so after 0 days how much money do you have when you have $100 because that's what you started with you haven't bought any lunches after buying one lunch well that means that you spent $4 how much money do you have left 96 after 2 days you've now spend how much money will another $4 and now you have $92 left after 5 days how much money have you spent will 5 days at $4 X you spent $20 so after starting with a hundred days take away $20 you're left with 80 how about 10 days after 10 days if you spent $4 each day you spent a total of $40 take that away from your original $100 how much money do you have $60 left at the graph for this notice said there are some numbers here but these numbers do not match what you have here so we need to scale it look at the scale for the X 0 1 2 5 and 10 1 2 3 4 5 6 7 8 9 10 so we can use these exact same numbers for our X scale done what about the scale for the Y to 8060 you know that this going to be zero we have 1 2 3 4 5 6 7 8 we have 8 lines how can we break this into a lines and reach a hundred from zero to a hundred you could split it every 20 that can fit or every 10 why every time it wouldn't fit 20 so we can go 20 40 60 80 so we'll go 20 40 60 80 100 okay you can split every 15 that could have worked out as well okay at zero we have a hundred so I'm going to .0 and 104 there's my first. At 1 I have 96 196 will be somewhere between here Canadian 100 at 2 I have 92 2 and 92 summer dress slightly below that Circle at 5 have a t v i have at 10 I have 60 10 is 60 notice which thoughts were approximated and which ones were not this. Right here was not across the mated this. Right here at 5 it's not a pressing mated this. Right here 0 on 100 which is this one was not a proximate it so when you're making your drawing your line it's important to know which. You're going to use I'm going to use the dots that represent exact positions on the graph then we go I'm going to use those thoughts there's my grass would you say that this is a increasing or decreasing function as you can see the light down so it is decreasing choose again second problem it cost $20 to go to a country fair that you have to pay $2 which game or right you wish to participate in show how much money you spent for every X game or ride you pay for it for you X's every game in front every right why is how much money do you spend but not never told me that why is going to be how much money I spent that because they wrote that for me it works show how much money you spent there telling you that that's what you have to show the Y which is the output is essentially what you were going to be showing so I know that why is how much money I spent that's how I knew that I had to label it that $1 because you have to get into the carnival in to get him to it says that it costs $20 right off the bat but if you go on one ride you spend $2 now you spent a total of $22 if you go onto rides will 2 * 2 is or let me say you spent $4 so now you spent a total of 24 what if you go on fire rides five rides at $2 a pop is going to be a total spent of $10 which means that now you spend 20 + 10 on rides you're a 30 and if you're at 10 rides at $2 a pop you spent a total of $20 or games and rides we have to have those $20 to your total of 20 or you reach 40 let's go ahead and grab this and see what we get again 0 to 10 is marked on the x-axis and that scale for us already nice and easy movie scale it well noticed that we have course you know that this number over here is going to be zero we have 20 30 40 we only have 8 lines here and we count by fives we can probably make it or she's me or if we come by 8 so we go age 16 before we can get a couple of numbers in there or we can go by fives items 8 will cover that give us this point not point 15 20 25 30 30 and 40 their first number I have zero and 2000 I have 23 as my first. Right there 12021 and 22 via. 2 and 24 would be at. Right above that but right below 25 5 and 30 would be 5 and 30 which is right here 10:40 would be this number tamassee 3 4 5 6 7 8 9 10 and 40 would be dis. Right here these five dots which ones were estimated which ones or not I did not estimate 10 + 40 5 and 30 or 0 and 20 those are exact thoughts it would be this. This. And that. So when I grab my ruler and I make my line I'm going to use those thoughts that were exactly perfectly graft on my graph paper and use that to make my grass or my life go ahead and that's the only way you going to fit this into your notebooks and on the back side please draw or write example number 303 you going to make a table for this equation there's a table but I'm going to show you right now is how to show work in the section here we go to my queen y equals 3x - 2 what I'm going to do is I'm going to substitute these X values into my equation so what does that mean that means I'm going to rewrite the equation except instead of writing X I'm going to ride a blank parentheses -2 what will I feel that space with the values in the table. Put a -2 in there here and it's all bad out 8 * -2 is -6 native 6-2 -8 got it that's negative 8 show the work again why equals x - 2/3 open parentheses -2 equals what number do I put in here I put a negative one this time if I -1 work it out three times negative one is negative 3 - 2 now -3 - 2 is -5 to my value here is going to be negative 5 do it again y equals 3x minus two three times open parentheses what number do I put in here but it is zero go ahead and work it out 0 - 2 0-2 is -2 Craigslist value is negative to throw you work again for this time for one y equals 3x - 2 3 times open parentheses -2 when do I put on here my next value is 1 but I want to hear Work It Out 3 * 1 is 3 - 2 give me a chance to go 3-2 going to be one who is value here is going to be one last y equals 3x - 2 equals 3 time open parentheses -2 word value will I place here can we go work 3 * 2 is 6 - 2 is 4 6-2 us for this value is for this is how you show work for this section I believe they're only 6 problems in your hand out so this work he's at the mechanics of pre-algebra please do not skip out on them thank you very much and I'll see you guys soon bye bye

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Video Notes 4.1, Day 1 of 2: Non-Proportional Relationships - - Math8

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