Answer:
x² + 6x + 9
Explanation:
[tex]\sf = \left(x+3\right)^2[/tex]
Use perfect square formula: (a + b)² = a² + 2ab + b²
[tex]= \sf x^2 + 2(x) (3) + 3^2[/tex]
simplify the following
[tex]= \sf x^2 + 6x +9[/tex]
Hence Maria is not correct. The correct answer is x² + 6x + 9.