Graph the relationship between y and x1 for x2 0 1 and 2-

Question

Graphing a second-order model. Consider the second-order model

y = 1 + x₁ - x₂ + x₁x₂ + 2x₁² + x₂²

(a) Graph the relationship between y and x₁ for x₂ = 0, 1, and 2.

(b) Are the graphed curves in part a first-order or second-order?

(c) How do the graphed curves in part a relate to each other?

(d) Do the independent variables x₁ and x₂ interact? Explain.