Because like terms you add or subtract together to make it easier to do the problem. just like you do with whole numbers. you add an subtract to make the answer simpler.
The graph increases untill day 4(slope= positive) and then is stays constant(slope=0). Starting at day 8 the slope changes to be negative
Answer:From the 8th day to the 10th day
Hope this helps:)
Let represents the total cost. We know for our problem that each yard of satin fabric costs $8.09, so yards will cost . similarly, each yard of cotton fabric costs $3.79, so yards will cost . We can also infer that the total cost, , will be the sum of the yards of satin fabric and the yards of cotton fabric, so:
Now, to determine the amount that Angeline would spend in all if she bought 5 yards of satin fabric and 8 yards of cotton fabric, we just need to replace and in our expression:
We can conclude that if Angeline would spend in all if she bought 5 yards of satin fabric and 8 yards of cotton fabric, she would spend $70.77
Let's begin ! ^_^
You have got informations in your problem that you just have to translate in a "mathematic language".
Company A :
"$40 membership fee and $2 per video stream."
Thanks to that, you can guess :
c = 40 + 2s
Now let's do the same thing to the company B.
Company B :
"charges a one-time $20 membership fee and $4 per video stream."
Therefore, c = 20 + 4s.
I think you have guessed !! =D And yes the system of equation that you have to solve and you're looking for is :
{c=40+2s ( Option B)
c=20+4s.
Second step : For how many video streams will the cost be the same for both companies?
We just have to solve the system :) And there is only one variable, the letter "s".
We know that we have to find equal costs as it is said in the question " the cost be the same for both companies", so :
=> 40 + 2s = 20 +4s
=> 4s - 2s = 40 - 20
=> 2s = 20
=> s = 20/2
=> s = 10
Verification :
Company A :
=> 40 + 2s = 40 + 2*10 = 40 + 20 =60.
Company B :
=> 20 + 4s = 20 + 4*10 = 20 + 40 = 60
As you have seen, the costs are the same for both companies.
We can say that as a conclusion for 10 video streams, the cost will be the same for both companies.
In short, the answer would be : 10.
Let me give you an advice : Usually the word "per" means a multiplication is the mathematic language.
Hope this helps !
Photon
