Question

Encontre as raizes das esquações !
a) x² - 3x +2 =0

b) - 4x²+ 8x -4= 0

Answer 1

a) x^2-3x+2=0
delta=b^2-4ac
delta=(-3)^2-4.1.2
delta=9-8
delta=1
x=-b-/+ raiz de delta/2a
x=-(-3)-1/2.1
x=3-1/2
x=2/2
x=1
x=-(-3)+1/2.1
x=3+1/2
x=4/2
x=2
b) -4x^2+8x-4=0
delta=b^2-4ac
delta=8^2-4.(-4).(-4)
delta=64-64
delta=0
x=-b-/+ raiz de delta/2a
x=-8-0/2.(-4)
x=-8/-8
x=1

Answer 2

d) - x² = - 7x +10
- x² + 7x - 10 = 0
a = - 1; b = 7; c = - 10

Δ = b² - 4ac
Δ = 7² - 4.(-1).(-10)
Δ = 49 + 4.(-10)
Δ = 49 - 40
Δ = 9

x = - b +/- √Δ  = - 7 +/- √9
          2a              2.(-1)

x = - 7 + 3 = - 4/(-2) = 2
         - 2

x = - 7 - 3 = - 10/ (-2) = 5
        - 2

R.: x = 2 e x = 5
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a)
x² - 3x + 2 = 0 
a = 1; b = - 3; c = 2

Δ = b² - 4ac
Δ = (-3)² - 4.1.2
Δ = 9 - 8
Δ = 1

x = - b +/- √Δ = - ( - 3) +/- √1
          2a                2.1

x = 3 + 1 = 4/2 = 2
        2

x = 3 - 1 = 2/2 = 1
        2

R.: x = 2 e x = 1
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b)
- 4x² + 8x - 4= 0 (: 4)
- x² + 2x - 1 = 0

a = - 1; b = 2; c = - 1

Δ = b² - 4ac
Δ = 2² - 4.(-1).(-1)
Δ = 4 + 4.(-1)
Δ = 4 - 4
Δ = 0

x = - b +/- √Δ = - 2 +/- 0
         2a              2.(-1)

x = - 2  =  2
      - 1

R.: x = 2