Question

 o numero 8 e a raiz da equacao  x²- 9x +18=0

Answer 1

x²-9x+18 = 0
Δ= (-9) - 4.1.18
Δ= 81 - 72
Δ= 9

-b +- √Δ / 2.a

-(-9) +- √9 / 2.1 

9+-3 / 2 =        9+3/2 = 12/2 = 6

                       9-3/2 = 6/2 = 3

Answer 2

 x²- 9x +18=0
a=1; b=-9; c=18
∆=b²-4ac⇒ ∆=(-9)²-4.1.18⇒ ∆=81-72⇒ ∆=9
x=-b±√∆ / 2.a⇒ x=-(-9)± √9 / 2.1⇒ x=9±3 / 2
x'-= 9+3/2⇒ x'=12/2⇒ x'=6
x''=9-3/2⇒ x''=6/2⇒ x''=3

S= {3,6}