Solve Complex A06875
1. **Problem statement:** Find the real values of $X$ and $Y$ that satisfy the equation $$X(X+i) + Y(Y - i) + i = 13.$$
2. **Rewrite the equation:** Expand the terms:
$$X^2 + Xi + Y^2 - Yi + i = 13.$$
3. **Separate real and imaginary parts:**
Real part: $$X^2 + Y^2 = 13.$$
Imaginary part: $$X - Y + 1 = 0.$$
4. **Solve the imaginary part for $Y$:**
$$Y = X + 1.$$
5. **Substitute $Y$ into the real part:**
$$X^2 + (X+1)^2 = 13.$$
6. **Simplify:**
$$X^2 + X^2 + 2X + 1 = 13,$$
$$2X^2 + 2X + 1 = 13,$$
$$2X^2 + 2X - 12 = 0,$$
$$X^2 + X - 6 = 0.$$
7. **Solve quadratic equation:**
$$X = \frac{-1 \pm \sqrt{1 + 24}}{2} = \frac{-1 \pm 5}{2}.$$
8. **Find roots:**
$$X_1 = 2, \quad X_2 = -3.$$
9. **Find corresponding $Y$ values:**
For $X=2$, $$Y = 2 + 1 = 3.$$
For $X=-3$, $$Y = -3 + 1 = -2.$$
**Final answers:**
$$\boxed{(X,Y) = (2,3) \text{ or } (-3,-2)}.$$