Answer:
-n+24/4n
Step-by-step explanation:
-1/4+6/n
-n+24/4n
Option (A) is correct
The sale this year be $400000 .
It is really simple. The ratio between both the triangles is 7, so you just divide 49 by 7(it gives you 7) to get the value of x. The answer is option (a) 7.
Hope This Helped!
Good Luck!
If the coefficient matrix has a pivot in each column, it means that it is shaped like this:
![A=\left[\begin{array}{cccc}a_{1,1}&a_{1,2}&a_{1,3}&a_{1,4}\\0&a_{2,2}&a_{2,3}&a_{2,4}\\0&0&a_{3,3}&a_{3,4}\\0&0&0&a_{4,4}\end{array}\right]](https://tex.z-dn.net/?f=A%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7Da_%7B1%2C1%7D%26a_%7B1%2C2%7D%26a_%7B1%2C3%7D%26a_%7B1%2C4%7D%5C%5C0%26a_%7B2%2C2%7D%26a_%7B2%2C3%7D%26a_%7B2%2C4%7D%5C%5C0%260%26a_%7B3%2C3%7D%26a_%7B3%2C4%7D%5C%5C0%260%260%26a_%7B4%2C4%7D%5Cend%7Barray%7D%5Cright%5D)
So, the correspondant system
will look like this:
![\left[\begin{array}{cccc}a_{1,1}&a_{1,2}&a_{1,3}&a_{1,4}\\0&a_{2,2}&a_{2,3}&a_{2,4}\\0&0&a_{3,3}&a_{3,4}\\0&0&0&a_{4,4}\end{array}\right]\cdot \left[\begin{array}{c}x_1\\x_2\\x_3\\x_4\end{array}\right] = \left[\begin{array}{c}b_1\\b_2\\b_3\\b_4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7Da_%7B1%2C1%7D%26a_%7B1%2C2%7D%26a_%7B1%2C3%7D%26a_%7B1%2C4%7D%5C%5C0%26a_%7B2%2C2%7D%26a_%7B2%2C3%7D%26a_%7B2%2C4%7D%5C%5C0%260%26a_%7B3%2C3%7D%26a_%7B3%2C4%7D%5C%5C0%260%260%26a_%7B4%2C4%7D%5Cend%7Barray%7D%5Cright%5D%5Ccdot%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx_1%5C%5Cx_2%5C%5Cx_3%5C%5Cx_4%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Db_1%5C%5Cb_2%5C%5Cb_3%5C%5Cb_4%5Cend%7Barray%7D%5Cright%5D)
This turn into the following system of equations:
The last equation is solvable for 
: we easily have
Once the value for is known, we can solve the third equation for 
:
(recall that is now known)
The pattern should be clear: you can use the last equation to solve for . Once it is known, the third equation involves the only variable . Once
Friendly phone= 0.06×400=24; 0.25×400= 100; 100+24+3.95=127.95; 127.95×4= $511.8
Chatter= 0.098 × 400= 39.2; 0.192 × 400= 76.8; 76.8+39.2+4.95= 120.95; 120.95 × 4= $483.8
Phone A Lot= 0.089 × 400= 35.6; 0.24 × 400= 96; 35.6 + 96= 131.6;
131.6 × 4= $526.4
Chatter < Friendly phone < Phone A Lot
$483.8 < $511.8 < $526.4
The cheapest one would be Chatter= $483.8
Hope this helps :)
