Answer:
Multiply row 1 by 
.
Step-by-step explanation:
The augmented matrix of the system of linear equation is described below:
![\left[\begin{array}{cccc}2&1&-1&-8\\0&2&3&-6\\-\frac{1}{2} &1&1&-4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D2%261%26-1%26-8%5C%5C0%262%263%26-6%5C%5C-%5Cfrac%7B1%7D%7B2%7D%20%261%261%26-4%5Cend%7Barray%7D%5Cright%5D)
Where 
, if we need to create 
, we need to multiply row 1 by , that is to say:
![\left[\begin{array}{cccc}1&\frac{1}{2} &-\frac{1}{2} &-4\\0&2&3&-6\\-\frac{1}{2} &1&1&-4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%26%5Cfrac%7B1%7D%7B2%7D%20%26-%5Cfrac%7B1%7D%7B2%7D%20%26-4%5C%5C0%262%263%26-6%5C%5C-%5Cfrac%7B1%7D%7B2%7D%20%261%261%26-4%5Cend%7Barray%7D%5Cright%5D)
Hence, the correct answer is: Multiply row 1 by .
Answer:
Approximately, 6.283..
Step-by-step explanation:
First calculate the area of the whole circle
We have radius(r)=4 cm
Area of circle(a)=pir^2
=pi×(4)^2
=pi×16
=Approximately,50.265......
A cirlce has a total of 360 degrees
Therefore,we can conclude 360 degrees=50.265...
or,1 degree=50.265/360
1 degree=Approximately,0.139
Now,
Area for the shaded region = Area of 45 degree
=0.139×45=Approximately,6.283.....
Therefore,the area of the shaded region is approximately,6.283....
