Respuesta :

harpreetsingh123456

Step-by-step explanation:

X2+ax+b=(x-9)(x+9)

X2+ax+b=x2-9x+9x-81

X2+ax+b=x2-81

therefore,a=0,b=(-81)

Then , ab = 0×-81 = 0

unicorn3125

Answer:

             B) 0

Step-by-step explanation:

x² + ax + b = (x – 9)(x + 9)

x² + ax + b = x² – 9x + 9x – 81

x² + ax + b = x² + 0x – 81

x²=x²      +ax = +0x        +b = -81

                    a = 0            b = -81

ab = 0(-81) = 0