Expression 3: 1 sixth "x" to the 4th power minus "a" squared "x" squared minus 2 left parenthesis, 2 "a" squared minus 4 , right parenthesis16x4−a2x2−22a2−4
3
Expression 4: negative left parenthesis, 4 "a" squared minus 16 thirds , right parenthesis "x" left brace, "x" greater than or equal to 2 , right brace−4a2−163xx≥2