Answer:
Emile made an error
Explanation:
Emile only took the positive part of the root as her answer, that is
8x² = 72 ( divide both sides by 8 )
x² = 9 ( take square root of both sides )
x = ±
= ± 3
that is x = - 3 , x = 3 ← is the correct solution
Andrea has the correct solution