Answer:
B
Step-by-step explanation:
x² + 9x
to complete the square
add ( half the coefficient of the x- term )² to x² + 9x
= x² + 2([tex]\frac{9}{2}[/tex] )x + ([tex]\frac{9}{2}[/tex] )²
= x² + 9x + [tex]\frac{81}{4}[/tex] ← the value of c
= (x + [tex]\frac{9}{2}[/tex] )² ← a perfect square
