Respuesta :

mrscriptixx

Answer:

1) x²-3x+9/4 = 81/4

2) x = 6, -3

Step-by-step explanation:

x²-3x-18=0

x²-3x=18

(b/2)² = (-3/2)² = 9/4; completing the square

x²-3x+9/4 = 18+9/4

(x-3/2)(x-3/2) = 81/4

x - 3/2 = ± 9/2

x = 3/2 ± 9/2

x = 6, -3