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
The standard form of an equation is

In the question, we have the following formula

To get the formula in standard form, we first have to subtract 2y from both sides (since we need to get 2y on the left side)

Finally we subtract 1 from both sides (since we need the number on the right side)

Hence, 4. is the correct answer.
You need to use division.