9th grade algebra problem is realllly hard, please help!! its about independent variables and slope HELP ASAP!?
here is the problem http://tinypic.com/r/2wpqo8p/7
its problem #1
i understand how to make the graph but what is the independent variable. i pretty much dont understand a-d on number one. same goers for #2 but i would like someone to help me on #1 and maybe ill understand #2.
PLEASE HELP ASAP. thank you!!!!
here is the problem http://tinypic.com/r/2wpqo8p/7
its problem #1
i understand how to make the graph but what is the independent variable. i pretty much dont understand a-d on number one. same goers for #2 but i would like someone to help me on #1 and maybe ill understand #2.
PLEASE HELP ASAP. thank you!!!!
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ok, the independent variable is the variable that is "controlling". When you write an equation with x and y, usually it is X. Also on graphs. So, we are laying tile. In hallways. Laying tile takes time. We have two observations, hallway length and time.
One is dependent on the other. Is the length of the hallway dependent on the time it takes to lay tile in it? No, of course not, that does not make sense. You don't change the length of the hall by taking longer to lay the tile in it.
But you do take longer to lay tile in a longer hallway. So the time is DEPENDENT on the length of the hallway.
When you just have a simple equation, the dependent variable may be presented on its own, like in E=mc^2, E is the dependent variable, m is the independent variable and c^2 is a constant.
OK, the slope of the variable. First we plot the data on a problem like this, I will use Microsoft Math,
(I hate yahoo answers, had to split it.)
show2d(plotDataSet2d(
{{3.5,85},{9.5,175},{17.5,295},
{4,92},{12,212},{8,153}}))
OK, the plot is almost an exact straight line, it is clear that either the tile was laid by a perfect machine or the data is artificial. None the less, we can see that it is linear, so we will make a straight line equation. The formula for the slope is (y2-y1)/(x2-x1) and there are no outliers so we will use the endpoints.
(295-85)/(17.5-3.5)
The slope is 15. So the meaning is that it takes about 15 minutes per foot to lay tile.
The next tthing is the y intercept. We can think about our equation in slope intercept form. What we know so far is:
y = 15x + b and they want us to find b. We can plug any old point into our equation and solve for b.
175= 15*9.5+b b = 32.5
If you think about it, this means that there is about a half hour constant overhead time, setup time, getting coffee time, buying supplies time, whatever, in every tile laying job.
y = 15x+32.5
time = 15*(foot of hallway)+ 32.5 minutes setup
Per your request I'll leave you the second one. Get Mcrosoft Math if you do not have it.
One is dependent on the other. Is the length of the hallway dependent on the time it takes to lay tile in it? No, of course not, that does not make sense. You don't change the length of the hall by taking longer to lay the tile in it.
But you do take longer to lay tile in a longer hallway. So the time is DEPENDENT on the length of the hallway.
When you just have a simple equation, the dependent variable may be presented on its own, like in E=mc^2, E is the dependent variable, m is the independent variable and c^2 is a constant.
OK, the slope of the variable. First we plot the data on a problem like this, I will use Microsoft Math,
(I hate yahoo answers, had to split it.)
show2d(plotDataSet2d(
{{3.5,85},{9.5,175},{17.5,295},
{4,92},{12,212},{8,153}}))
OK, the plot is almost an exact straight line, it is clear that either the tile was laid by a perfect machine or the data is artificial. None the less, we can see that it is linear, so we will make a straight line equation. The formula for the slope is (y2-y1)/(x2-x1) and there are no outliers so we will use the endpoints.
(295-85)/(17.5-3.5)
The slope is 15. So the meaning is that it takes about 15 minutes per foot to lay tile.
The next tthing is the y intercept. We can think about our equation in slope intercept form. What we know so far is:
y = 15x + b and they want us to find b. We can plug any old point into our equation and solve for b.
175= 15*9.5+b b = 32.5
If you think about it, this means that there is about a half hour constant overhead time, setup time, getting coffee time, buying supplies time, whatever, in every tile laying job.
y = 15x+32.5
time = 15*(foot of hallway)+ 32.5 minutes setup
Per your request I'll leave you the second one. Get Mcrosoft Math if you do not have it.