Question

X + y = 12

Answer 1

We are given with two equations to find the values of two variables, hence the problem can be solved.

Adding the two equations:

x + y = 12x - y = 10
2x    = 22
x =11
y = 1

Answer 2

Answer:

Option C is correct

value of the x-determinant for the system is, -2

Step-by-step explanation:

Given the system of equation:

x + y =12

x -y =10

Represents the system of equations in matrix format:

$\begin{bmatrix} 1 & 1\\ 1 & -1 \end{bmatrix}\begin{bmatrix}x\\y\end{bmatrix} = \begin{bmatrix}12\\ 10\end{bmatrix}$

Now, to find the determinant of a matrix.

Formula for the determinant of matrix:

$\begin{bmatrix}a & b\\ c & d\end{bmatrix} = ad-bc$

then;

The value of the x-determinant:

$\begin{bmatrix}1 & 1\\ 1 & -1\end{bmatrix}$

Using determinant(D) formula:

$D= (1)(-1)-(1)(1) = -1 -1 = -2$

Therefore, the value of the x-determinant for the system is, -2