Which ordered pair [tex]$(a, b)$[/tex] is the solution to the following system of equations?
[tex]\[
\left\{
\begin{array}{c}
-2a + 3b = 14 \\
a - 4b = 3
\end{array}
\right.
\][/tex]

A. [tex]$(-13, -4)$[/tex]
B. [tex]$(-4, -13)$[/tex]
C. [tex]$\left(16 \frac{10}{11}, \frac{8}{11}\right)$[/tex]
D. [tex]$(-4, 13)$[/tex]



Answer :

To solve the given system of equations, we need to find the values of [tex]\(a\)[/tex] and [tex]\(b\)[/tex] that satisfy both equations:

[tex]\[ \left\{\begin{array}{c} -2a + 3b = 14 \\ a - 4b = 3 \end{array}\right. \][/tex]

### Step-by-Step Solution

1. Solve for [tex]\(a\)[/tex] in the second equation:
[tex]\[ a - 4b = 3 \quad \Rightarrow \quad a = 4b + 3 \][/tex]

2. Substitute [tex]\(a = 4b + 3\)[/tex] into the first equation:
[tex]\[ -2(4b + 3) + 3b = 14 \][/tex]

3. Simplify the equation:
[tex]\[ -8b - 6 + 3b = 14 \][/tex]
[tex]\[ -5b - 6 = 14 \][/tex]

4. Solve for [tex]\(b\)[/tex]:
[tex]\[ -5b = 14 + 6 \][/tex]
[tex]\[ -5b = 20 \][/tex]
[tex]\[ b = -4 \][/tex]

5. Substitute [tex]\(b = -4\)[/tex] back into [tex]\(a = 4b + 3\)[/tex] to find [tex]\(a\)[/tex]:
[tex]\[ a = 4(-4) + 3 \][/tex]
[tex]\[ a = -16 + 3 \][/tex]
[tex]\[ a = -13 \][/tex]

### Verification

We have found that [tex]\((a, b) = (-13, -4)\)[/tex]. Let's verify this solution by substituting these values back into the original equations:

1. Substitute into the first equation:
[tex]\[ -2(-13) + 3(-4) = 14 \][/tex]
[tex]\[ 26 - 12 = 14 \][/tex]
[tex]\[ 14 = 14 \quad \text{(True)} \][/tex]

2. Substitute into the second equation:
[tex]\[ -13 - 4(-4) = 3 \][/tex]
[tex]\[ -13 + 16 = 3 \][/tex]
[tex]\[ 3 = 3 \quad \text{(True)} \][/tex]

The values satisfy both equations.

### Conclusion

The ordered pair [tex]\((-13, -4)\)[/tex] is a solution to the system of equations. Among the given choices:
[tex]\[ (-13, -4) \][/tex]
[tex]\[ (-4, -13) \][/tex]
[tex]\[ \left(16 \frac{10}{11}, \frac{8}{11}\right) \][/tex]
[tex]\[ (-4,13) \][/tex]

The correct choice is the first one, [tex]\((-13, -4)\)[/tex]. Therefore, the answer is:
[tex]\[ \boxed{1} \][/tex]