Question

Escreva as equações na forma geral e resolva
b) – 20 = - x - x2
c) 13 – 2x – 15x2 = 0
d) (x - 1).(x - 2) = 6

Answer 1

Resposta:

-20= -x-x²

-x²-x+20

∆=b²-4ac

∆= (-1)²-4*(-1)*20

∆= 1+80

∆= 81

x½= -b±√∆/2a

x½= 1±√81/2*(-1)

x½= 1±9/-2

x1= 1+9/-2

x1= 10/-2

x1= -5

x2= 1-9/-2

x2= -8/-2

x2= 4

d) (x-1).(x-2)= 6

x²-3x-4=0

∆= b²-4ac

∆= (-3)²-4*1*(-4)

∆= 9+16

∆= 25

x½= -b±√∆/2a

x½= 3±√25/2*1

x1= 3+5/2

x1=4

x2= 3-5/2

x2=-1

espero ter ajudado

obrigado