Question

9 x ao quadrado menos 1 igual a zero

Answer 1

9x² - 1 = 0
9x² = 1
x² = 1/9
x = √1/9
x = 1/3     ok

Answer 2

9x² - 1= 0

9x²= 0 + 1

9x²= 1

x²= 1/9

x= ± √1/9

x= ± 1/3

S= (1/3 , - 1/3)