Verified answer

Resposta:

Explicação passo a passo:

a.

a=1

b=-5

c=6

x=5+-V(-5)²-4.1.6/2.1

x=5+-V25-24/2

x=5+-V1/2

x=5+-1/2

x'=5+1/2=6/2=3

x''=5-1/2=4/2=2

S={2,3}

b.

a=2

b=-8

c=8

x=8+-V(-8)²-4.2.8/2.2

x=8+-V64-64/4

x=8+-V0/4

x=8/4=2

S={2}

c.

a=6

b=1

c=-1

x=-1+-V1²-4.6.-1/2.6

x=-1+-V1+24/12

x=-1+-V25/12

x=-1+-5/12

x'=-1-5/12=-6/12=-1/2

x''=-1+5/12=4/12=1/3

S={-1/2;1/3}

d.

2x²-7x-15=0

a=2

b=-7

c=-15

x=7+-V(-7)²-4.2.-15/2.2

x=7+-V49+120/4

x=7+-V169/4

x=7+-13/4

x'=7+13/4=20/4=5

x''=7-13/4=-6/4=-3/2

S={-3/2;5}

e.

x²-4x+9=0

a=1

b=-4

c=9

x=4+-V(-4)²-4.1.9/2.1

x=4+-V16-36/2

x=4+-V-20/2

Não existe solução, porque não existe raiz quadrada de número negativo

f.

a=1

b=-8

c=12

x=8+-V(-8)²-4.1.12/2.1

x=8+-V64-48/2

x=8+-V16/2

x=8+-4/2

x'=8+4/2=12/2=6

x''=8-4/2=4/2=2

S={2,6}

g.

a=1

b=-4

c=-5

x=4+-V(-4)²-4.1.-5/2.1

x=4+-V16+20/2

x=4+-V36/2

x=4+-6/2

x'=4+6/2=10/2=5

x''=4-6/2=-2/2=-1

S={-1,5}