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Algebra Lesson 3-4 Slope Intercept Form (Day 2)

Added Nov 03, 2017 •

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okay so there could be a 2 in lesson 3 4 on slope intercept form yesterday we wrote and graph linear equation in slope intercept form and today we're modeling real world data with equations in slope intercept form so we have to just two examples left today and example for says what is the equation I am flipping her set form for the line shown in the graph so we're going to have a grass here in a second but I want to check in the book we are in the back on page 173 I want to make sure I didn't Overlook anything so here's a graph and they want us to write the equation of the line in the graph so we need to know the Andy y intercepts so where is the Line crossing the y-axis -3. Goes right here and to find the slope we actually just did this on her work she didn't me you are going to well find the slope using like so far -3 will go up to and forward one rise to run one so what's the slope that's it super easy Here Comes yours what is the equation in slope intercept form for the line shown in the graph so this one's yours example for Mike let me forget to do so we still need to go over the homework forgot that piece after we went over the warm a pie yeah we should have time what's the y intercept so where does that go does it go here or here that's the slow I have it right here. The slope goes in front of the at the Y intercept is the constant triggers for being positive or isn't that Robin going down from left to right simple popular slope so where is that Line crossing the y-axis so where you going to put it one out look on us okay and then how do you find the slope start at 1 and do what pepper down down how many if you go down one then you're going to go over what okay we don't know so I wouldn't go just down one I would keep going down okay so what is -3/1 there are you just -3 right okay guys is coughing the white office at 1 that's the y intercept from there we want to go and find another Point that's on the add an intersection so we need to go down one two three and then forward 1 what's -3/1 minus 3 it looks like it's going to go down 6 and over the simplified fraction and that means you could have gone down 3 forward for and there should be a point at that intersection so if you overlook that and you go down 6 and forward 8 and that reduces to -3/4 then go and check and I bet there's a point at down 3 Florida can you just overlooked it okay questions on that laugh example maximum heart rate for a 25 year old exercising to burn fast is 117 beats per minute for every 5 years older than 25 the ideal rate drops 3 beats per minute so after the age of 25 the ideal maximum heart rate is 117 beats per minute oh I don't know about that mean I'm just reading the problem so we'd have to look that up for every 5 years older than 25 the ideal rate drops 3 beats per minute write an equation to find the ideal maximum heart rate for anyone over 25 who is exercising to burn fat flatbread equation and then find the ideal maximum heart rate for a 55 year old so let's start with a y equals MX plus b can you tell me which number represents the slope and which number represents the y intercept the y intercept skip Chris Chris we will be using Brewery DIY is the Beats right because for the y 3 bits dropping 3 beats per minute why would be in sport with a slope or talking about the slope and the y-intercept okay you're defining a variable Zacks represents what hey Ma so if a person is 25 then we know the answers 117 if the person 30 then what happens because it went down 3 beats per minute for that 5 years so wouldn't that be the rate of change for slope yes -3 is our slope okay 117 is the initial at age 25 the ideal heart rate is 117 then forever years that we had queso abscess 5 every time we add five years so one five year. It would drop 3 to 5 year. drop Six every 5 years it goes down 3 so if x was one five year. It would go down 3 text was to five year. It was go down to * 3 is 6 so now we're going to go so I really don't I need all four quadrants in this because we're talking about age and heart rate okay and neither of those are going to be negative so I'd really we only need to be in the first car that's one 17 now it's going down from there okay so we want to go by what so don't start well if you do there he's probably shouldn't skip up so we should just pick one go by 20s or go by 30s or so I'm just going to put a 20 here which is actually going by tens on mine I'm just skipping other every other line 40 80 or 60 I can't count 8100 so 120 117 would be about right here right okay and then we're going down 3 and forward one for each okay so since we're going by 20s here let's make that a more usable is in what's divisible to give us -3 21 / 7 / 5 down 15 / 5 just to help you so you can you're not just going down one and four or three cuz I would be kind of hard sorry down 3 and 4 worldwide if we go down on 15 from 117 where would we be 102 and then over 1 2 3 4 5 and then if we go down another 15 what's 101 where we at 102 - 15th 1585 so 87 and this is 9787 / 5 okay that's not very straight Warriors if you put 5 in you getting ready to 15 + 117 is 102 yes Chris so we're going down three and over one where does the one come from I-75 and then and so then I just I can go to. To -15/5 which is the same thing as -3/1 but I chose 15 over 5 because to go down three and four word one with the scale we use would be you know different do you see what I'm saying makes sense so I picked the -15/5 which is the same thing as -3 over 155 person how many years how many five curious is that after 25 so what's 55 minus 25 and how many 5-year periods is that so or 5/6 what did we get at that point 102 so find me ideal maximum heart rate for a 55 year old 102 beats per per minute BPM okay flash try this one hey Madam he went on Christmas gifts has increased by an average of 150000 or .15 million per year since 1986 consumers read over 3 million dollars in 1986 write a linear equation to find the average amount d plans for any year n since 1986 they didn't tell us to you special variables here today okay so they just asking us to use d&n rather than X and Y so they would replace your why I don't know why did because we're talking about money spent dollars good okay thank you for clarifying that for me and then ask for number Meers okay so that's all it's the same y equals MX plus b that they're using D $4 and end for number of years since 1986 so what's the plural what part rapper what's the slope 50000 right it's increasing 150000 per year hey so that you can put a hundred fifty thousand for your slope or .15 million that's why they they gave that to you cuz to write 150000 as it's easier to be .15 but you have to remember when you go to find your answer that the slope is in millions okay .15 million + I'm what's the y intercept 1986 since 1986 consumer spent 3 million in 1986 I did that to you when I Reddit 3 million is the initial amount I don't know we're going to find out yeah sorry 3 but remember we wrote this is all so what he is also in millions we have to keep that in mind when we go to find her answer okay for now we're going to go after it .15 is 1500 K .15 Main 1500 which reduces by 5 to 3:20 so when we go to do our slope we can rise three 20 so that means I want to go by maybe tens here cuz I'm run 20 this one's yard you're doing it with me right the Y intercept 3 and I'm going to Ride 3 and run 20 so I can go ahead and go by ones on my y-axis start 3 and then write 3 1 2 3 and run 20 rice 1 2 3 run 20 again it doesn't make sense for an to B- cuz we're talking about number of years since 1986 and it doesn't make sense for D to be negative because that would mean they're spending money which is not possible really needs to graph in the first quadrant and then find the amount of money spent by consumers in 1999 how many years is that after 1986 99 - 86 is 13 so this was 1013 be about right here rice that was 345 it looks like about 10 million how can we check so we can put 13 right in for an so we can find a dollars by multiplying .15 by 13 because it's 13 years after 1986 and then add 3 are you doing that you should be doing all this on your paper this is your problem so take .15 x 13 1.9 so that's 1.95 + 3 4.95 so Porter $95,000 what corner toilet 4000900 + 950000 right yes it is and let me check that I why can't I have a different problem here does that make sense let's see 2003 million 13 years 3 million dollars over 13 years you're in car sorry 13 years started with $3000000 here increasing .15 million for 13 years Chris you will have a real world at least one real world problem yes okay 174 Edison NJ assignment on graph paper I bet there's some graphing involved 13 problems 12 13 14 16 18 through 34 is every other even and then 3650 54 and 56 reviewing some stuff from yesterday and now an example for remember all you have to do is write the equation and then yesterday a couple of applications it's up here on the front table and I need to

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Algebra Lesson 3-4 Slope Intercept Form (Day 2)

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