Question

Determine os valores de x nas equaçoes do 2° grau a seguir:

a) x² - 5x + 6 = 0
b) x² - 8x + 12 = 0
c) x² + 2x - 8 = 0
d) x² - 5x + 8 = 0
e) 2x² - 8x + 8 = 0
f) x² - 4x -5 = 0
g) -x² + x + 12 = 0
H) 6x² + x - 1 = 0
j) 3x² -7x + 2 = 0
Gente por favor vale nota. Para amanha

Answer 1

a) x^2-5x+6=0
delta=b^2-4ac
delta=(-5)^2-4.1.6
delta=25-24
delta=1
x=-b-/+ raiz de delta/2a
x=-(-5)-1/2.1
x=5-1/2
x=4/2
x=2
x=-(-5)+1/2.1
x=5+1/2
x=6/2
x=3
b) x^2-8x+12=0
delta=b^2-4ac
delta=(-8)^2-4.1.12
delta=64-48
delta=16
x=-b-/+ raiz de delta/2a
x=-(-8)-4/2.1
x=8-4/2
x=4/2
x=2
x=-(-8)+4/2.1
x=8+4/2
x=12/2
x=6
c) x^2+2x-8=0
delta=b^2-4ac
delta=2^2-4.1.(-8)
delta=4+32
delta=36
x=-b-/+ raiz de delta/2a
x=-2-6/2.1
x=-8/2
x=-4
x=-2+6/2.1
x=4/2
x=2
d) x^2-5x+8=0
delta=b^2-4ac
delta=(-5)^2-4.1.8
delta=25-32
delta=-7
delta negativo, não há raízes reais
e) 2x^2-8x+8=0
delta=b^2-4ac
delta=(-8)^2-4.2.8
delta=64-64
delta=0
x=-b-/+ raiz de delta/2a
x=-(-8)-0/2.2
x=-8-0/4
x=-8/4
x=-2
f) x^2-4x-5=0
delta=b^2-4ac
delta=(-4)^2-4.1.(-5)
delta=16+20
delta=36
x=-b-/+ raiz de delta/2a
x=-(-4)-6/2.1
x=4-6/2
x=-2/2
x=-1
x=-(-4)+6/2.1
x=4+6/2
x=10/2
x=5
g) -x^2+x+12=0
delta=b^2-4ac
delta=1^2-4.(-1).12
delta=1+48
delta=49
x=-b-/+ raiz de delta/2a
x=-1-7/2.(-1)
x=-8/-2
x=4
x=-1+7/2.(-1)
x=6/-2
x=-3
h) 6x^2+x-1=0
delta=b^2-4ac
delta=1^2-4.6.(-1)
delta=1+24
delta=25
x=-b-/+ raiz de delta/2a
x=-1-5/2.6
x=-6/12 (:6)
x=-1/2
x=-1+5/2.6
x=4/12 (:4)
x=1/3
j) 3x^2-7x+2=0
delta=b^2-4ac
delta=(-7)^2-4.3.2
delta=49-24
delta=25
x=-b-/+ raiz de delta/2a
x=-(-7)-5/2.3
x=7-5/6
x=2/6 (:2)
x=1/3
x=-(-7)+5/2.3
x=7+5/6
x=12/6
x=2