Answer:
Step-by-step explanation:
given is a system of linear equations in 3 variables as

This can be represented in matrix form as
AX=B Or
![\left[\begin{array}{ccc}-1&-4&2\\1&2&-1\\1&1&-1\end{array}\right] *\left[\begin{array}{ccc}x\\y\\z\end{array}\right] =\left[\begin{array}{ccc}-10\\11\\14\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-1%26-4%262%5C%5C1%262%26-1%5C%5C1%261%26-1%5Cend%7Barray%7D%5Cright%5D%20%2A%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%5C%5Cy%5C%5Cz%5Cend%7Barray%7D%5Cright%5D%20%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-10%5C%5C11%5C%5C14%5Cend%7Barray%7D%5Cright%5D)
So solution set
X would be 
|A|=-1(-1)+4(0)+2(-1)=--1
Cofactors of A are
-1 0 -1
-2 -1 -3
0 1 2
So inverse of A is
1 2 0
0 1 -1
1 3 -2
Solution set would be
x=12
y=-3
z=-5
Answer: £83.70
Step-by-step explanation:
We can set up a ratio.
Let x be the amount he earns for 9 hours of work.

We can cross multiply:
x = 9*9.3
x = £83.70
We are given with two equations 2x − 3y = −1 and <span>11x − 9y = −13. The problem says that when the first equation is multiplied by -3 which results to -6x + 9y = 3, the sum of the resulting equation and the second one is equal to 5x = -10. We verify this: -6x + 11x = 5x while -9 y and 9 y cancels out. 3+-13 equals -10. Hence the total is really 5x = - 10.</span>
Answer:
320 Customers took the survey
Step-by-step explanation: