Question

qual é às respostas?

Answer 1

a)
x²+9x+8=0

a=1; b=9; c=8;

Δ=b²-4.a.c
Δ=9²-4.1.8
Δ=81-32
Δ=49

x=-b+-√Δ/2a
x=-9+-√49/2

x'=-9+7/2 = -2/2 = -1
x"=-9-7/2 = -16/2 = -8

b)
9x²-24x+16=0

a=9; b=-24; c=16;

Δ=b²-4.a.c
Δ=(-24)²-4.9.16
Δ=576-576
Δ=0

x=-b+-√Δ/2a
x=24+-√0/18

x'=24+0/18 = 24/18 = 4/3
x"24-0/18 = 24/18 = 4/3

c)
x²-2x+4=0

a=1; b=-2; c=4;

Δ=b²-4.a.c
Δ=(-2)²-4.1.4
Δ=4-16
Δ=-12

R = ∅ (vazio pois o delta é negativo)

d)
3x²-15x+12=0

a=3; b=-15; c=12;

Δ=b²-4.a.c
Δ=(-15)²-4.3.12
Δ=225-144
Δ=81

x=-b+-√Δ/2a
x=15+-√81/6

x'=15+9/6 = 24/6 = 4
x"=15-9/6 = 6/6 = 1

e)
10x²+72x-64=0

a=10; b=72; c=-64;

Δ=b²-4.a.c
Δ=72²-4.10.(-64)
Δ=5184+2560
Δ=7744

x=-b+-√Δ/2a
x-72+-√7744/20

x'=72+88/20 = 160/20 = 8
x"=72-88/20 = -16/20 = -4/5