Answer:
1st option
Step-by-step explanation:
x² - 19x + n
using the method of completing the square
add ( half the coefficient of the x- term )² to x² - 19x
x² + 2(- [tex]\frac{19}{2}[/tex] )x + (- [tex]\frac{19}{2}[/tex] )²
with n = (- [tex]\frac{19}{2}[/tex] )² = [tex]\frac{361}{4}[/tex] , then
(x - [tex]\frac{19}{2}[/tex] )² ← a perfect square trinomial
