Rational Constrained Choice (X,*, x2 )is interior (b The slope of the indiff curve at(x,", X2 )equals the slope of the budget constraint X1Rational 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