Question

dentre os numeros -2,0,1,4, quais deles sao raizes da equação x2-2x-8=0

Answer 1

x^2-2x-8=0
delta=b^2-4.a.c
delta=(-2)^2-4.1.(-8)
delta=4+32
delta=36
x=-b-/+ raiz de delta/2a
x=-(-2)-6/2.1
x=2-6/2
x=-4/2
x=-2
x=-(-2)+6/2.1
x=2+6/2
x=8/2
x=4
-2 e 4

Answer 2

x²-2x-8=0
Δ=(-2)²-4.1.(-8)=0
Δ=4+32
Δ=36

x=-(-2)+-√36
     2.1

x`=2+6  =8 =4
    2        2

x¨=2-6= -4=-2
   2       2

logo V {4 e -2}