Question

Use a fórmula de Bháskara e resolva as equações, sendo U = IR:

A) 9x² + 8x - 1 = 0

B) -2x² + 9x + 18 = 0

C) 6x² + x - 1 = 0

Answer 1

a) a=9, b=8, c=-1
Δ = b²-4ac
Δ = 8²-4*9*(-1)
Δ = 64+36
Δ = 100

x = (-b+-√Δ)/2a
x = (-8+-√100)/2*9
x = (-8+-10)/18

x' = (-8+10)/18
x' = 2/18, ou 1/9

x'' = (-8-10)/18
x'' = -18/18
x'' = -1


b) a=-2, b=9, c=18
Δ = 9²-4*(-2)*18
Δ = 81+144
Δ = 225

x = (-9+-√225)/2*(-2)
x = (-9+-15)/-4

x' = (-9+15)/-4
x' = 6/-4, ou 3/-2

x'' = (-6-15)/-4
x'' = -21/-4


c) a=6, b=1, c=-1
Δ = 1²-4*6*(-1)
Δ = 1+24
Δ = 25

x = (-1+-√25)/2*6
x = (-1+-5)/12

x' = (-1+5)/12
x' = 4/12 ou 1/3

x'' = (-1-5)/12
x'' = -6/12 ou -1/2