Question

Resolva as seguintes equações do 2o grau:
a) X2 + 2x – 8 = 0
b) X2 – 14x + 49 = 0
c) X2 – 5x + 8 = 0
d) X2 – 9 = 0
e) 2x2 – 5x = 0
f) 2x2 = 5x – 8

Answer 1

Explicação passo-a-passo:

a= 1 b= 2 c= -8

D =2²-4.1

D =4+32

D =36

x' =-2 +6

2 .1

x' =-2+6

2

x' =4

2

x' =2

x" =-2 -6

2 .1

x" =-2-6

2

x" =-8

2

x" =-4

a= 1 b= -14 c= 49

D =-14²-4.1

D =196-196

D =0

x' =-(-14) +0

2 .1

x' =14+0

2

x' =14

2

x' =7

x" =-(-14) -0

2 .1

x" =14-0

2

x" =14

2

x" =7

a= 1 b= -5 c= 8

D =-5²-4.1

D =25-32

D =-7

a= 1 b= 0 c= -9

D =0²-4.1

D =0+36

D =36

x' =-0 +6

2 .1

x' =0+6

2

x' =6

2

x' =3

x" =-0 -6

2 .1

x" =0-6

2

x" =-6

2

x" =-3

a= 2 b= -5 c= 0

D =-5²-4.2

D =25-0

D =25

x' =-(-5) +5

2 .2

x' =5+5

4

x' =10

4

x' =2,5

x" =-(-5) -5

2 .2

x" =5-5

4

x" =0

4

x" =0

a= 2 b= -5 c= 8

D =-5²-4.2

D =25-64

D =-39