Question

1) Resolva as equaçoes incompletas do 2 grau sendo U=R
a)5x^2-3125=0
b)9x^2-3x=0
c)x^2-81=0
d)2x^2+6x=0
e)-6x^2+6x=0

Answer 1

Resposta:

a)5x²-3125=0

x²=3125/5

x=raiz de (625)

x=25

b)9x²-3x=0

a=9 b=-3 c=0

x=-(-3)+ou- raiz de(3²-4.9.0)/2.9

x=3 +ou- raiz de(9-0)/18

x'=3+3/18

x'=6÷6/18÷6

x'=1/3

x"=3-3/18

x"=0

c)x²-81=0

x²=81

x=raiz de(81)

x=9

d)2x²+6x=0

a=2 b=6 c=0

x=-6 +ou- raiz de(6²-4.2.0)/2.2

x=-6 +ou- raiz de(36-0)/4

x'=-6+6/4

x'=0

x"=-6-6/4

x"=-12÷4/4÷4

x"=-3/1

e)-6x²+6x=0

a=-6 b=6 c=0

x=-6 +ou- raiz de(6²-4.-6.0)/2.-6

x=-6 +ou- raiz de(36-0)/-12

x'=-6+6/-12

x'=0

x"=-6-6/-12

x"=-12/-12

x"=1