So we are given the system:
Written in matrix form we get:
![\left[\begin{array}{cc}2&4\\6&3\end{array}\right] \left[\begin{array}{c}x\\y\end{array}\right] = \left[\begin{array}{c}8\\-3\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D2%264%5C%5C6%263%5Cend%7Barray%7D%5Cright%5D%20%0A%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5Cend%7Barray%7D%5Cright%5D%20%3D%0A%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D8%5C%5C-3%5Cend%7Barray%7D%5Cright%5D%20)
We compute the solution like this:
![ \left[\begin{array}{c}x\\y\end{array}\right] = \left[\begin{array}{cc}2&4\\6&3\end{array}\right] ^{-1} \left[\begin{array}{c}8\\-3\end{array}\right] \\= \left[\begin{array}{cc}-3&4\\6&-2\end{array}\right] \left[\begin{array}{c}8\\-3\end{array}\right] \dfrac{1}{18}\\= \left[\begin{array}{c}2\\-3\end{array}\right]](https://tex.z-dn.net/?f=%20%0A%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5Cend%7Barray%7D%5Cright%5D%20%3D%0A%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D2%264%5C%5C6%263%5Cend%7Barray%7D%5Cright%5D%20%5E%7B-1%7D%0A%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D8%5C%5C-3%5Cend%7Barray%7D%5Cright%5D%20%20%5C%5C%3D%0A%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D-3%264%5C%5C6%26-2%5Cend%7Barray%7D%5Cright%5D%0A%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D8%5C%5C-3%5Cend%7Barray%7D%5Cright%5D%20%5Cdfrac%7B1%7D%7B18%7D%5C%5C%3D%0A%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D2%5C%5C-3%5Cend%7Barray%7D%5Cright%5D)
The solution is :
![\left[\begin{array}{c}2\\-3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D2%5C%5C-3%5Cend%7Barray%7D%5Cright%5D)
Answer:
atq= let no.be x and y
x= 4y-3.......(1)
x-2y=7....(2)
subtracting both eqn
x-x+2y=4y-3-7
2y=4y-10
-2y= -10
y=5 ........second no.
first no...x=7+2y=7+10=17.......first no....
That answer will be 7.
Explanation:
=1-3+9
=10-3
=7
Answers:
So the solution is (x,y) = (4, -1)
=============================================================
Work Shown:
6x + 7y = 17
6x + 7( y ) = 17
6x + 7( -3x+11 ) = 17 ... replace every copy of y with -3x+11
6x - 21x + 77 = 17
-15x = 17-77
-15x = -60
x = -60/(-15)
x = 4
We'll use this x value to find y
y = -3x+11
y = -3(4)+11 ... replace x with 4
y = -12+11
y = -1
We have x = 4 and y = -1 pair up together to give us the solution (x,y) = (4, -1)
------------------------
To check the solution, we plug x = 4 and y = -1 into each equation
Plugging the values into the first equation leads to...
y = -3x+11
-1 = -3(4)+11
-1 = -1
This is effectively already done in the last part of the previous section. But it doesn't hurt to verify like this regardless.
We'll need to verify the second equation as well.
6x + 7y = 17
6(4) + 7(-1) = 17
24 - 7 = 17
17 = 17
We get a true equation, so the solution is confirmed with both equations. Overall, the solution to the system of equations is confirmed. This system is independent and consistent.
Answer:
She has 11/20 yds left
Step-by-step explanation:
We take what she had and subtract what she gave away
9/10 - 7/20
We need to get a common denominator of 20
9/10 *2/2 - 7/20
18/20 - 7/20
11/20
She has 11/20 yds left
