Question

(4,4)
x+y=-11
-4x+y=5

Explanation:

Step1: Subtract the two equations to eliminate \( y \)

We have the system:
\[

$$\begin{cases} x + y = -11 \quad (1)\\ -4x + y = 5 \quad (2) \end{cases}$$

\]
Subtract equation (2) from equation (1):
\[
(x + y) - (-4x + y) = -11 - 5
\]
Simplify the left - hand side: \( x + y + 4x - y=5x \), and the right - hand side: \( - 16 \). So we get \( 5x=-16 \), then \( x =-\frac{16}{5}=-3.2 \)

Step2: Substitute \( x \) into equation (1) to find \( y \)

Substitute \( x = - 3.2 \) into \( x + y=-11 \), we have \( -3.2 + y=-11 \)
Add 3.2 to both sides of the equation: \( y=-11 + 3.2=-7.8 \)

Now we check if the point \( (4,4) \) is a solution. Substitute \( x = 4 \) and \( y = 4 \) into the first equation: \( 4+4 = 8
eq-11 \). Substitute into the second equation: \( - 4\times4 + 4=-16 + 4=-12
eq5 \). So \( (4,4) \) is not a solution of the system of equations.

Answer:

The point \( (4,4) \) is not a solution of the system \(

$$\begin{cases}x + y=-11\\-4x + y = 5\end{cases}$$

\)