Rational Constrained choice (X,*, X2 )is interior (b The slope of the indiff curve at ( X,* X2 * )equals the slope of the budget constraintRational Constrained Choice x1 x2 x1 * x2 * (x1 *,x2 *) is interior . (b) The slope of the indiff. curve at (x1 *,x2 *) equals the slope of the budget constraint