Question

1) Utilizando a fórmula de bhaskara resolva as equações do 2º grau:

a) x²-x-6=0

b) x²+x-20=0

c) x²+3x-4=0

d) x²+5x+6=0

e) x²-2x-3x=0

Answer 1

Fórmulas: Δ = b²-4ac
x= -b ± √Δ / 2a
a) x²-x-6=0
 Δ = 1² -4.1.-6 = 1+4.6 = 25
√Δ= ± 5
x' = -6 + 5 / 2 = -1/2
x'' = -6 - 5 / 2 = -11/2
b) x²+x-20=0
Δ = 1² + 4.20 = 81
√Δ= +9, -9
x'= -1 + 9/2 = 8/2 = 4
x''= -1-9/2 = -10/2 =-5
c) x²+3x-4+0
Δ= 9+16 = 25
x'= -3+5/2 = 2/2 = 1
x''= -3-5/2 = -8/2 = -4
d) x²+5x+6=0
Δ= 25-24 = 1
x'= -5+1/2 = -4/2 = -2
x''= -5-1/2 = -6/2 = -3
e) x² - 2x -3x=0
x² - 5x=0
Δ= 25. 4.1.0
√Δ = +5, -5
x'= +5+5/2 = 5
x''= +5-5/2 = 0