Question

Qual o valor de x = -b +(raiz qudrada de b² - 4 ac ) 

a=5, b= -9 e c = -2

Answer 1

$x = - b + \sqrt{b^2 - 4ac} \\ x = - (- 9) + \sqrt{(- 9)^2 - 4 \times (5) \times (- 2)} \\ x = 9 + \sqrt{81 + 40} \\ x = 9 + \sqrt{121} \\ x = 9 + \sqrt{11^2} \\ x = 9 + 11 \\ \boxed{x = 20}$