Solve the system of equations by elimination.

[tex]\[
\left\{
\begin{array}{l}
-12x - 15y = -9 \\
-4x - 5y = -3
\end{array}
\right.
\][/tex]

A. [tex]\((2, -7)\)[/tex]

B. [tex]\((-2, -7)\)[/tex]

C. [tex]\((-2, -5)\)[/tex]

D. Infinite number of solutions



Answer :

To solve the system of equations using elimination, follow these steps:

Given equations:
[tex]\[ \left\{\begin{array}{l} -12x - 15y = -9 \quad \text{(Equation 1)} \\ -4x - 5y = -3 \quad \text{(Equation 2)} \end{array}\right. \][/tex]

### Step 1: Align the equations
Align both equations for easy comparison:
[tex]\[ \begin{array}{rcl} -12x - 15y & = & -9 \quad \text{(Equation 1)} \\ -4x - 5y & = & -3 \quad \text{(Equation 2)} \end{array} \][/tex]

### Step 2: Manipulate the equations to eliminate a variable
First, modify Equation 2 to make the coefficient of [tex]\(x\)[/tex] equal to the coefficient of [tex]\(x\)[/tex] in Equation 1. To do this, multiply Equation 2 by 3:
[tex]\[ 3 \cdot (-4x - 5y) = 3 \cdot (-3) \][/tex]
[tex]\[ -12x - 15y = -9 \quad \text{(Equation 3)} \][/tex]

Now we have:
[tex]\[ \begin{array}{rcl} -12x - 15y & = & -9 \quad \text{(Equation 1)} \\ -12x - 15y & = & -9 \quad \text{(Equation 3)} \end{array} \][/tex]

### Step 3: Compare the equations
Notice that Equation 1 and Equation 3 are identical. Subtracting Equation 3 from Equation 1 results in:
[tex]\[ (-12x - 15y) - (-12x - 15y) = -9 - (-9) \][/tex]
[tex]\[ 0 = 0 \][/tex]

### Step 4: Interpret the result
The result [tex]\(0 = 0\)[/tex] indicates that the two original equations are essentially the same. This means that the system of equations does not have a unique solution. Instead, the equations represent the same line, implying an infinite number of solutions.

### Conclusion
The system of equations:
[tex]\[ \left\{\begin{array}{l} -12x - 15y = -9 \\ -4x - 5y = -3 \end{array}\right. \][/tex]
has an infinite number of solutions, which means any point [tex]\((x, y)\)[/tex] that satisfies one equation will automatically satisfy the other.