Question

1-achar o valor de delta das equaçoes :
a-x^2+7x+5=0
b-3x^2+x+2=0
c-4x^2-70x+10=0
d12x^2-x-3=0


2-determine as raizes das esquaçoes do 2 grau .
a-4x^2+11x-3=0
b-3x^2+4x+1=0
c)-x^2+12x+20=0
d-2x^2+3x+1=0

Answer 1

1)
a) x²+7x+5=0
∆= 7²-4*1*5
∆=49-20
∆=29

b) 3x²+x+2=0
∆=1²-4*3*2
∆=1-24
∆=23

c) 4x²-70x+10=0
∆=(-70)²-4*4*10
∆=4900-160
∆=4740

d) 12x²-x-3=0
∆=(-1)²-4*12*(-3)
∆=1+144
∆=145

2)

a) 4x²+11x-3=0
∆=11²-4*4*(-3)
∆=121-48
∆=73

x= -11+/-√73/8

b) 3x²+4x+1=0
∆=4²-4*3*1
∆=16-12
∆=4

x= -4+/-√4/2*3
x=-4+/-4/6
x'=-4+4/6
x'=0/6
x'=0
x"=-4-4/6
x"=-8/6. divide por 2
x"-4/3

c) x²+12x+20=0
∆=12²-4*1*20
∆=144-80
∆=64

x=-12+/-√64/2*1
x=-12+/-8/2
x'=-12+8/2
x'=-4/2
x'=-2
x"=-12-8/2
x"=-20/2
x"=-10

d)2x²+3x+1=0
∆=3²-4*2*1
∆=9-8
∆=1

x= -3+/-√1/2*2
x=-3+/-1/4
x'=-3+1/4
x'=-2/4
x"=-3-1/4
x"=-4/4
x"=-1