Question

resolva as seguintes equações do 2° grau, identifique os coeficientes e determine as raízes se existir.
1) x²-8x+12=0
2) x²-5x+8=0
3) 2x²-8x+8=0
4) x²-4x-5=0
5) 3x²-7x+2=0
6) 2x²-7x=15
7) x²=x=12

Answer 1

1) x^2-8x+12=0
a=1 b=-8 c=12
delta=b^2-4ac
delta=(-8)^2-4.1.12
delta=64-48
delta=16
x=-b-/+ raiz de delta/2a
x=-(-8)-4/2.1
x=8-4/2
x=4/2
x=2
x=-(-8)+4/2.1
x=8+4/2
x=12/2
x=6
2) x^2-5x+8=0
a=1. b=-5. c=8
delta=b^2-4ac
delta=(-5)^2-4.1.8
delta=25-32
delta=-7
delta negativo não há raizes reais
3) 2x^2-8x+8=0
a=2 b=-8. c=8
delta=b^2-4ac
delta=(-8)^2-4.2.8
delta=64-64
delta=0
x=-b-/+ raiz de delta/2a
x=-(-8)-0/2.2
x=8-0/4
x=8/4
x=2
4) x^2-4x-5=0
a=1 b=-4 c=-5
delta=b^2-4ac
delta=(-4)^2-4.1.(-5)
delta=16+20
delta=36
x=-b-/+ raiz de delta/2a
x=-(-4)-6/2.1
x=4-6/2
x=-2/2
x=-1
x=-(-4)+6/2.1
x=4+6/2
x=10/2
x=5