The numbers x,y and z are given by x =[tex]\sqrt{12-3\sqrt{7} } - \sqrt{12 + 3\sqrt{7} } , y = \sqrt{7-4\sqrt{3 } } - \sqrt{7 + 4\sqrt{3} } and z = \sqrt{2 + \sqrt{3} } - \sqrt{2 - \sqrt{3} }[/tex] . What is the value of x,y and z