Respuesta :

x^2 - 81 = 0. Add 81 to each side.

x^2 = 81. Take the square root of each side.

x = 9, -9

Answer:

–9, 9

Step-by-step explanation:

x² – 81 = 0

Add 81 to each side

x² – 81+81 = 0+81

x^2 = 81

Take the square root of each side

sqrt(x^2) = ± sqrt(81)

x = ± 9