Question

Me ajudem ? equação de 2 grau

Answer 1

b) x(x-5)+10=4
x²-5x+10-4=0
x²-5x+6=0
A=1 B=-5 C=6
x=-(-5)+-√(-5)²-4.1.6 / 2
x=5+-√25-24 / 2
x=5+-√1 / 2
x=5+-1 / 2
x1=5+1/2=6/2=3
x2=5-1/2=4/2=2
S={3, 2}

c) 2x(4x-1)=21
8x²-2x=21
8x²-2x-21=0
A=8 B=-2 C=-21
x=-(-2)+-√(-2)²-4.8.(-21)/2.8
x=2+-√4+672/16
x=2+-√676/16
x=2+-26/16
x1=2+26/16=28/16=1,75
x2=2-26/16=-24/16=-1,5
S={1,75, -1,5}

d) x(x-2)=2(x+6)
x²-2x=2x+12
x²-2x-2x-12=0
x²-4x-12=0
A=1 B=-4 C=-12
x=-(-4)+-√(-4)²-4.1.(-12)/2
x=4+-√16+48/2
x=4+-√64/2
x=4+-8/2
x1=4+8/2=12/2=6
x2=4-8/2=-4/2=-2
S={6, 2}

e) x(2x-1)+6=4(x-1)
2x²-x+6=4x-4
2x²-x+6-4x+4=0
2x²-5x+10=0
A=2 B=-5 C=10
x=-(-5)+-√(-5)²-4.2.10/2.2
x=5+-√25-80/4
Vai dar raiz negativa, então não tem solução.

f) (x-1).(x-2)=6
x²+2x-x+2-6=0
x²+x-4=0
A=1 B=1 C=-4
x=-1+-√1²-4.1.(-4)/2
x=-1+-√1+16/2
x=-1+-√17/2
x=-1+-4,12/2
x1=-1+4,12/2=3,12/2=1,56
x2=-1-4,12/2=-5,12/2=-2,56
S={1,56, -2,56}

Bom, eu cansei, rs. Espero ter sido útil. :)