Answer:
A book is worth $1 and a DVD is worth $12.
Step-by-step explanation:
The equations (2 unknowns and two equations, d is for a DVD and b is for a book):
For David: 3d+4b=40
For Anna: d+6b=18
Now multiply the second equation with -3 and add to the first equation:
3d+4b=40
−3d−18b=−54
Combined equation: −14b=−14 and b=1 (means that each book is worth $1).
Now for DVD price, use the second equation:
d=18−6 or d=12 (means that each DVD is worth $12).
A book is worth $1 and a DVD is worth $12.
Answer:
x = 4
Step-by-step explanation:
given 2 chords intersecting inside a circle , then
the product of the parts of one chord is equal to the product of the parts of the other chord, that is
9 × 4x = 8(4x + 2)
36x = 32x + 16 ( subtract 32x from both sides )
4x = 16 ( divide both sides by 4 )
x = 4
In this question, we are given a matrix, and we have to perform the given operation.
The matrix is:
![\left[\begin{array}{ccc}6&-1&|5\\1&-5&|0\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D6%26-1%26%7C5%5C%5C1%26-5%26%7C0%5Cend%7Barray%7D%5Cright%5D)
The following operation is given:
In which 
is the element at the first line and 
is the element at the second line.
Updating the first line:
Thus, the filled matrix will be given by:
![\left[\begin{array}{ccc}0&29&|5\\1&-5&|0\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%2629%26%7C5%5C%5C1%26-5%26%7C0%5Cend%7Barray%7D%5Cright%5D)
For another example where row operations are applied on a matrix, you can check brainly.com/question/18546657
A=bh which means 900=50x18
Answer: 
<u>Step-by-step explanation:</u>
The coordinate at -30° <em>(-30° = 330°)</em> = 
the x-value is 
the y-value is 
