Question

qual a raiz quadrada de x elevado a 2 menos 20 menos x igual a zero

Answer 1

(x^2 - 20 - x)^1/2 = 0
[(x^2 - 20 - x)^1/2]^2 = 0^2
x^2 - x - 20 = 0

x1 + x2 = -b/a = 1
x1 . x2 = c/a = -20

x1 = 5 e x2 = -4