Question

   x² - bx = -2    de tal modo que as raizes sejam iguais
  




b² = 8  ??

Answer 1

 x² - bx = -2 

 x² - bx +2 = 0

Δ = b² - 4.a.c
Δ= 8 - 4.1.2 = 8-8=0

x1 = 8 +/-√0 ==> x = 8 +/- 0
            2.1                  2

x1=x2 = 4