1)Resolva as equações do 2º grau: a) x² – 3x – 4 = 0 (R: -1, 4...
b) x² + 8x + 16 = 0 (R: -4)
c) 3x² – 2x – 1 = 0 (R: -1/3, 1)
d) x² – 7x + 15 = 0 ( 5 e 2)
e) 9x² – 6x + 1 = 0 (1/3)
f) 3x² – 7x + 2 = 0
g) –3x² + 6x = 0 (0 e 2)
h) 2x² - 7x = 15 (R: 5, -3/2)
i) 4x² -12x+ 9 = 0 (R: 3/2)
j) x² -x-12= (R: -3 , 4)
k) 2x²+12x+18 = 0 (R: -3 )
l) 25x² -20x+4 = 0 (R: 2/5)
m) x² + 5x + 6 = 0 (R:-2,-3)
m) x² - 7x + 12 = 0 (R:3,4)
o) x² + 5x + 4 = 0 (R:-1,-4)
p) x² - 18x + 45 = 0 (R:3,15)
q) -x² - x + 30 = 0 (R:-6,5)
u) x² - 6x + 9 = 0 (R:3)
1 Resposta
1) x2 - 5x + 6=0
a=1 ∆=b²-4.a.c x=-b+-√∆/2a
B=-5 ∆=25-4.1.6 x=5 + - √1/2
c=6 ∆=25-24 x=5+ - 1/2
∆= 1 x1=5+1/2
x1=6/2 x1= 3
x2=5-1/2
x2=4/2 x2=2
2)
a=1 ∆= b²-4.a.c x=-b + - √∆/2a
B= -8 ∆= 64-48 x=8+-√16/2.1
c=12 ∆= 16 x= 8+-4/2
x1=8+4/2 x1=12/2
x1= 6
x2=8-4/2 x2=4/2=2
3)
a=1 ∆=b² -4.a.c x= -b +-√∆/2a
B=2 ∆= 4+32 x=-2+-√36/2.1
c=-8 ∆=36 x=-2+-6/2
x1=-2+6/2 x1=4/2
x1=2
x2=-2-6/2 x2=-8/2
x2=-4
4)
a=1 ∆=b²-4a.c R)não existe raiz de
B=-5 ∆=25-64 número negativo.
c=8 ∆= -39
5)
a=2 ∆=b² -4.a.c x=-b + -√∆/2a
B=-8 ∆=64 -64 x=8+-√0/2.2
c=8 ∆=0 x=8/4 x=2
6)
a=1 ∆=b² - 4.a.c x=-b + - √∆/2a
B=-4 ∆=16+20 x=4+-√36/2.1
c=-5 ∆=36 x=4-+6/2
x1=4+6/2 x1=10/2
x1=5
x2=4-6/2 x2=-2/2
x2=-1
7)
a=-1 ∆=b² - 4.a.c x=-b + - √∆/2a
B=1 ∆=1+48 x=-1+-√49/2.1
c=12 ∆=49 x=-1+-7/2
x1=-1+7/2 x1=6/2=3
x2=-1-7/2
x2=-8/2 x2=-4
8)
a=-1 ∆=b² - 4.a.c x=-b + - √∆/2a
B=6 ∆=36-20 x=-6+-√16/2.(-1)
c=-5 ∆=16 x=-6+-4/-2
x1=-6+4/-2
x1=-2/-2 x1=-1
x2=-2-4/-2
x2=-6/-2 x=3
9)
a=6 ∆=b² - 4.a.c x=-b + - √∆/2a
B=1 ∆=1+24 x=-1+-√25/2a
c=-1 ∆=25 x=-1+-5/12
x1=-1+5/12 x1=4/12
x1=1/3
x2=-1-5/12 x2=-6/12
x2=-1/2
10)
a=3 ∆=b² - 4.a.c x=-b + - √∆/2a
B=-7 ∆=49-24 x=7-+√25/2.3
c=2 ∆=25 x=7+-5/6
x1=7+5/6 x1=12/6
x1=2
x2=7-5/6 x2=2/6
x2=1/3
11)
a=2 ∆=b² - 4.a.c x=-b + - √∆/2a
B=-7 ∆=49+120 x=7+-√169/2.2
c=-15 ∆=169 x=7+-13/4
x1=7+13/4 x1=20/4
x1=5
x2=7-13/4 x2=-6/4
x2=-3/2
12)
a=4 ∆=b² - 4.a.c x=-b + - √∆/2a
B=-12 ∆=144-144 x=12+-√0/2.4
c=9 ∆=0 x=12/8 x=3/2
13)
a=1 ∆=b² - 4.a.c x=-b + - √∆/2a
B=-1 ∆=1+48 x=1+-√49/2.1
c=-12 ∆=49 x=1+-7/2
x1=1+7/2 x1=8/2
x1=4
x2=1-7/2 x2=-6/2
x2=-3
14)
a=2 ∆=b² - 4.a.c x=-b + - √∆/2a
B=12 ∆=144-144 x=-12+-√0/2.2
c=18 ∆=0 x=-12/4 x=-3
15)
a=-4 ∆=b² - 4.a.c não possuí raiz
B=9 ∆=18+16 real
c=0 ∆=34
16)
a=25 ∆=b² - 4.a.c x=-b + - √∆/2a
B=-20 ∆=400-400 x=20+-√0/2.25
c=4 ∆=0 x=20/50 x=2/5
17)
a=-1 ∆=b² - 4.a.c não existe raiz de
B=2 ∆=4-60 número negativo.
c=-15 ∆=-56
18)
a=1 ∆=b² - 4.a.c não existe raiz de
B=3 ∆=6-8 número negativo.
c=2 ∆=-2
19)
a= 1 ∆=b² - 4.a.c não existe raiz de
B= 1 ∆=1-48 número negativo.
c=12 ∆=-47
20)
a=1 ∆=b2 - 4.a.c x=-b + - √∆/2a
B=-2 ∆=4-4 x=2+-√0/2.1
c=1 ∆=0 x=2/2 x=1
21)
a=1 ∆=b2 - 4.a.c x=-b + - √∆/2a
B=6 ∆=36-36 x=-6+-√0/2.1
c=9 ∆=0 x=-6/2 x=-3
Espero ter ajudado ;-)
Mais perguntas de Matemática
Top Semanal
Top Perguntas
![Toda Materia](https://escolaeducacao.org/assets/images/element/01.webp)
Você tem alguma dúvida?
Faça sua pergunta e receba a resposta de outros estudantes.