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Current time:0:00Total duration:2:00

Video transcript

let's see we have this graph over here with T is the independent variable on the on the horizontal axis and D is the dependent variable on the vertical axis and then they have a table here looks like this table corresponds to this graph when T equals 1 D is for T when T is equal to 2 D is a T so these points correspond to points on this line and then they explain to us you are buying a gym membership the membership costs $40 per month and the graph and table above D is the number total number of dollars that you pay for your gym membership so that's D right over there and T is the time in months that you keep the membership write an equation for the amount of money D that you pay for your gym membership if you keep the membership 40 months and you see that here if you're one month you pay $40 two months you pay another four dollars you pay $80 you see that in the graph right over here if you have zero months you pay nothing then one month $40 the next month another $40 getting you to 80 so if I were to write this as an equation well the dependent variable here is the amount that I pay in dollars so that is going to depend on the time and how is it going to depend on the time in months well I'm going to pay $40 per month times the number of months so I can either write it as 40 with a little asterisk sign which is shift 8 or I could literally and then I put T there or I could literally put just a T right over there and I think that's right because if I if if my time is 0 according to this table and according to this graph I pay nothing if there was some initial membership charge then maybe we would add that membership charge and you would pay the monthly fee after that but here this looks about right that the dollars paid is equal to 40 40 times the time in month the time in months is the independent variable it drives the dependent variable the number of dollars you pay