Question

Resolva as equações do 2° em R

a) X^2-8x+15=0
b)X^2+10x+25=0
c)3X^2+4x+1=0
d)-X^2+12x-20=0

me ajudem pfv^-^

Answer 1

resposta

a) x^2-8x+15=0

a=1 b= -8 c= 1

¤=b^2-4.a.1

¤= (-8)^2-4.1.15

¤=64-60

¤=4

x= -b+_V¤^2.a

x= -(-8)+_V4/2.1

x=8+_2/2

x'= 8+2/2

x'=10/2

x"= 5

x"=8-2/2

x"= 6/2

x"=3

S={5,3}

b)X^2+10x+25=0

a= 1 b= 10 c= 25

a=1 b= 10 c= 25

¤=b^2-4.a.c

¤=10^2-4.1.25

¤= 100-100

¤=0

x= -b+_V¤/2.a

x= 10+_V0/2.1

x'=10+0/2

x'= 10/2

x'= 5

x"=10-0/2

x"= 10/2

x"= 5

S={5,5}

c)3X^2+4x+1=0

a=3 b= 4 c 1

¤= b^2-4.a.c

¤= 4^2-4.3.1

¤=16-12

¤=4

x=-b+_V¤/2.a

x=4+_V4/2.3

x=4+_2/6

x'= 4+2/6

x'=6/6

x'= 1

x"=4-2/6

x"=2/6

x"=1/3

S={1, 1/3}

d)-X^2+12x-20=0

a= -1 b= 12 c= -20

¤= b^2-4.a.c

¤= 12^2-4.-1(-20)

¤=144-80

¤=64

x= -b+_V¤/2.1

x= -12+-V64/2.-1

x= -12+_8/-2

x'= -12+8/-2

x'= -2/-2 (-1)

x'=2/2

x'=1

x"= -12-8/-2

x"= -20/-2 (-1)

x"= 20/2

x"=10

S={1,1}