Which ordered pair is a solution to the system of linear equations?

[tex]\[
\begin{array}{l}
x + 3y = -4 \\
y = -3x - 4
\end{array}
\][/tex]

A. [tex]\((-1, -1)\)[/tex]
B. [tex]\((1, 1)\)[/tex]
C. [tex]\((1, -1)\)[/tex]
D. [tex]\((-1, 1)\)[/tex]



Answer :

To determine which ordered pair is a solution to the given system of linear equations:
[tex]\[ \begin{array}{l} x + 3y = -4 \\ y = -3x - 4 \end{array} \][/tex]
we need to check each provided ordered pair by substituting them into both equations to see which pair satisfies both equations simultaneously.

### Checking each ordered pair:

1. Pair [tex]\((-1, -1)\)[/tex]:
- Substitute [tex]\( x = -1 \)[/tex] and [tex]\( y = -1 \)[/tex] into the first equation:
[tex]\[ -1 + 3(-1) = -1 - 3 = -4 \][/tex]
This satisfies the first equation.
- Substitute [tex]\( x = -1 \)[/tex] into the second equation:
[tex]\[ y = -3(-1) - 4 = 3 - 4 = -1 \][/tex]
This satisfies the second equation.

Therefore, [tex]\((-1, -1)\)[/tex] satisfies both equations.

2. Pair [tex]\((1, 1)\)[/tex]:
- Substitute [tex]\( x = 1 \)[/tex] and [tex]\( y = 1 \)[/tex] into the first equation:
[tex]\[ 1 + 3(1) = 1 + 3 = 4 \][/tex]
This does not satisfy the first equation (left-hand side is 4, not -4).

Therefore, [tex]\((1, 1)\)[/tex] is not a solution.

3. Pair [tex]\((1, -1)\)[/tex]:
- Substitute [tex]\( x = 1 \)[/tex] and [tex]\( y = -1 \)[/tex] into the first equation:
[tex]\[ 1 + 3(-1) = 1 - 3 = -2 \][/tex]
This does not satisfy the first equation (left-hand side is -2, not -4).

Therefore, [tex]\((1, -1)\)[/tex] is not a solution.

4. Pair [tex]\((-1, 1)\)[/tex]:
- Substitute [tex]\( x = -1 \)[/tex] and [tex]\( y = 1 \)[/tex] into the first equation:
[tex]\[ -1 + 3(1) = -1 + 3 = 2 \][/tex]
This does not satisfy the first equation (left-hand side is 2, not -4).

Therefore, [tex]\((-1, 1)\)[/tex] is not a solution.

### Conclusion:
The only ordered pair that satisfies both equations in the system is [tex]\((-1, -1)\)[/tex]. Therefore, [tex]\((-1, -1)\)[/tex] is the solution to the system of equations.