To solve the system of equations:
- \( x^2 + y^2 = 61 \)
- \( x - y + 10 = 9 \)
Let's start with the second equation to express \(y\) in terms of \(x\):
From the equation \( x - y + 10 = 9 \):
\[ x - y = -1 \]
This simplifies to:
\[ y = x + 1 \]
Now, we can substitute \(y = x + 1\) into the first equation:
\[ x^2 + (x + 1)^2 = 61 \]
Expanding the second term:
\[ x^2 + (x^2 + 2x + 1) = 61 \]
Combining like terms:
\[ 2x^2 + 2x + 1 = 61 \]
Next, we subtract 61 from both sides:
\[ 2x^2 + 2x + 1 - 61 = 0 \]
This simplifies to:
\[ 2x^2 + 2x - 60 = 0 \]
We can divide the entire equation by 2:
\[ x^2 + x - 30 = 0 \]
Now, we can factor this quadratic equation:
\[ (x + 6)(x - 5) = 0 \]
Setting each factor equal to zero gives:
\[ x + 6 = 0 \quad \Rightarrow \quad x = -6 \] \[ x - 5 = 0 \quad \Rightarrow \quad x = 5 \]
Now, we can find the corresponding \(y\) values for each \(x\):
For \(x = -6\): \[ y = -6 + 1 = -5 \]
For \(x = 5\): \[ y = 5 + 1 = 6 \]
Thus, the solution pairs \((x, y)\) are:
\[ (-6, -5) \quad \text{and} \quad (5, 6) \]
So the final solutions to the system of equations are:
\[ (x, y) = (-6, -5) \quad \text{and} \quad (5, 6) \]