Question

Calcule as raizes das equações:
a) x²-7x+10
b) x²+3x
c) -6x²+12

Answer 1

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

Δ = b² - 4ac
Δ = (-7)² - 4.1.10
Δ = 49 - 40
Δ = 9

x = - b +/- √Δ = - ( - 7) +/-√9
          2a              2.1

x' = 7 + 3 = 10/2 = 5
         2

x" = 7 - 3 = 4/2 = 2
         2

x = 5 e x = 2

b)
x² + 3x = 0
x(x + 3) = 0
x = 0

x + 3 = 0
x = - 3

c)
- 6x² + 12 = 0
- 6x² = - 12  ( -1)
6x² = 12
x² = 12/6
x² = 2
x = √2