### Instruction: If $(x + y)^2 = 1$ and $xy = -4$, what is the value of $x^2 + y^2$?### Response: I notice that the problem involves the square of a binomial, which can be expanded using the formula $(x + y)^2 = x^2 + 2xy + y^2$.
If I substitute the given values of $(x + y)^2$ and $xy$, I get $1 = x^2 + 2(-4) + y^2$.
Simplifying, I obtain $x^2 + y^2 = 1 + 8 = 9$.