Answer :

To solve the system of equations using the addition method, we'll go through the following steps:

1. Write the System of Equations:
We start with the given system of equations:
[tex]\[ \begin{aligned} -5x & = 6y + 1 \qquad \text{(Equation 1)} \\ 5y & = -2 - 3x \qquad \text{(Equation 2)} \end{aligned} \][/tex]

2. Standardize the Form of Equations:
Rearrange both equations to have all variables and constants on one side of the equations:
[tex]\[ \begin{aligned} -5x - 6y & = 1 \qquad \text{(Equation 1)} \\ 3x + 5y & = -2 \qquad \text{(Equation 2)} \end{aligned} \][/tex]

3. Eliminate a Variable:
Multiply Equation 1 by 3 and Equation 2 by 5 to align the coefficients of [tex]\(x\)[/tex]:
[tex]\[ \begin{aligned} 3(-5x - 6y) & = 3(1) \\ -15x - 18y & = 3 \qquad \text{(Equation 3)} \end{aligned} \][/tex]
[tex]\[ \begin{aligned} 5(3x + 5y) & = 5(-2) \\ 15x + 25y & = -10 \qquad \text{(Equation 4)} \end{aligned} \][/tex]

4. Add the New Equations to Eliminate [tex]\(x\)[/tex]:
Now add Equation 3 and Equation 4 to eliminate [tex]\(x\)[/tex]:
[tex]\[ \begin{aligned} (-15x - 18y) + (15x + 25y) & = 3 + (-10) \\ (-15x + 15x) + (-18y + 25y) & = -7 \\ 0 + 7y & = -7 \\ 7y & = -7 \\ y & = -1 \end{aligned} \][/tex]

5. Substitute [tex]\(y = -1\)[/tex] Back into One of the Original Equations:
Substitute [tex]\(y = -1\)[/tex] back into Equation 1:
[tex]\[ -5x - 6(-1) = 1 \\ -5x + 6 = 1 \\ -5x = 1 - 6 \\ -5x = -5 \\ x = 1 \][/tex]

6. Write the Solution:
The solution to the system is [tex]\(x = 1\)[/tex] and [tex]\(y = -1\)[/tex].

Thus, the solution set is [tex]\((1, -1)\)[/tex]. This means the system has a single unique solution where [tex]\(x = 1\)[/tex] and [tex]\(y = -1\)[/tex].