If \(x (4 - \sqrt{3}) = y (4 + \sqrt{3}) = 1\), then the value of \(x^2 + y^2\) will be \(\cfrac{38}{169}\).
We have: \[ x = \cfrac{1}{(4 - \sqrt{3)}} = \cfrac{(4 + \sqrt{3})}{(4 - \sqrt{3})(4 + \sqrt{3})} = \cfrac{(4 + \sqrt{3})}{16 - 3} = \cfrac{(4 + \sqrt{3})}{13} \] \[ y = \cfrac{1}{(4 + \sqrt{3)}} = \cfrac{(4 - \sqrt{3})}{(4 + \sqrt{3})(4 - \sqrt{3})} = \cfrac{(4 - \sqrt{3})}{16 - 3} = \cfrac{(4 - \sqrt{3})}{13} \] Therefore: \[ x^2 + y^2 = \left(\cfrac{4 + \sqrt{3}}{13}\right)^2 + \left(\cfrac{4 - \sqrt{3}}{13}\right)^2 = \cfrac{(4 + \sqrt{3})^2 + (4 - \sqrt{3})^2}{169} \] Now simplify: \[ (4 + \sqrt{3})^2 + (4 - \sqrt{3})^2 = 2[(4)^2 + (\sqrt{3})^2] = 2(16 + 3) = 38 \] So the final value is: \[ x^2 + y^2 = \cfrac{38}{169} \]