Question

resolver em r as seguintes equacoes do 2 grau
a)X ao quadrado - 6x -7=0
b)7x ao quadrado -6x-1=0
c)2x ao quadrado -3x-2=0
d)8x ao quadrado +6x-2=0
e)2x ao quadrado +6x-8=0
f) X ao quadrado +18X+17=0
g)X ao quadrado +6x-7=0
h)7X ao quadrado +6x-1=0
i)2x ao quadrado +3x-2=0
j)8x ao quadrado -6x -2=0
k)2x ao quadrado -6x-2=0
l)x ao quadrado -18x+17=0

Answer 1

a) ∆ =b²-4AC
∆ =(-6)²-4(1)(-7)
∆ =36+28
∆ =64

x'=-(-6)+8/2=14/2=7
x"=-(-6)-8/2=-2/2=-1

b) ∆ =b²-4AC
∆ =(-6)²-4(7)(-1)
∆ =36+28
∆ =64
x'=-(-6)+8/2×7=14/14=1
x"=-(-6)-8/2×7=-2:2/14:2=-1/7

c) ∆ =b²-4AC
∆ =(-3)²-4(2)(-2)
∆ =9+16
∆ =25

x'=-(-3)+5/2×2=8/4=2
x"=-(-3)-5/2×2=-2:2/4:2=-1/2

d) ∆ =b²-4AC
∆ =(6)²-4(8)(-2)
∆ =36+64
∆ =100
x'=-(6)+10/2×8=4:4/16:4=1/4
x"=-(6)-10/2×8=-16:2/14:2=-8/7

e) ∆ =b²-4AC
∆ =(6)²-4(2)(-8)
∆ =36+64
∆ =100

x'=-(6)+10/2×2=4/4=1
x"=-6-10/2×2=16/4=4

f) ∆ =b²-4AC
∆ =(18)²-4(1)(17)
∆ =334-64
∆ =256

x'=-18+16/2=-2/2=-1
x"=-18-16/2=34/2=17

g) ∆ =b²-4AC
∆ =(6)²-4(1)(-7)
∆ =36+28
∆ =64

x'=-6+8/2=2/2=1
x"=-6-8/2=-14/2=-7

h) ∆ =b²-4AC
∆ =(6)²-4(7)(-1)
∆ =36+28
∆ =64

x'=-6+8/2×7=2:2/14:2=1/7
x"=-6-8/2×7=14/14=1

i) ∆ =b²-4AC
∆ =(3)²-4(2)(-2)
∆ =25

x'=-3+5/2×2=2:2/4:2=1/2
x"=-3-5/2×2=-8/4=-2

j) ∆ =b²-4AC
∆ =(-6)²-4(8)(-2)
∆ =36+64
∆ =100

x'=-(-6)+10/2×8=16/16=1
x"=-(-6)-10/2×8=-4:4/16:4=1/4

k) ∆ =b²-4AC
∆ =(-6)²-4(2)(-2)
∆ =36+16
∆ =64

x'=-(-6)+8/2×2=14:2/4:2=7/2
x"-(-6)-8/2×2=-2:2/4:2=-1/2

l) ∆ =b²-4AC
∆ =(-18)²-4(1)(17)
∆ =324-68
∆ =256

x'=-(-18)-16/2=2/2=1
x"=-(-18)+16/2=34/2=17