Question

Admitindo u = R resolva as equaçoes do 2° grau:

x² - 12x =0
x² - 1 =0
x² - 16 =0
5x² - 3x =0

Answer 1

x^2-12x=0
delta=b^2-4ac
delta=(-12)^2-4.1.0
delta=144-0
delta=144
x=-b-/+ raiz de delta/2a
x=-(-12)-12/2.1
x=12-12/2
x=0/2
x=0
x=-(-12)+12/2.1
x=12+12/2
x=24/2
x=12
x^2-1=0
x^2=0+1
x^2=1
x= raiz de 1
x=-/+ 1
x^2-16=0
delta=b^2-4ac
delta=0^2-4.1.(-16)
delta=0+64
delta=64
x=-b-/+ raiz de delta/2a
x=-0-8/2.1
x=-8/2
x=-4
x=-0+8/2.1
x=8/2
x=4
5x^2-3x=0
delta=b^2-4ac
delta=(-3)^2-4.5.0
delta=9-0
delta=9
x=-b-/+ raiz de delta/2a
x=-(-3)-3/2.5
x=3-3/10
x=0/10
x=0
x=-(-3)+3/2.5
x=3+3/10
x=6/10 (:2)
x=3/5

Answer 2

a) 
x² - 12x = 0
x ( x - 12 ) = 0
x = 0
x - 12 = 0 ⇒ x = 12
x' = 0
x" = 12

b) 
x² - 1 = 0
x² = 1
x = + - √1
x = + - 1
x' = - 1
x" = 1

c) 
x² - 16 = 0
x² = 16
x = + - √16
x = + - 4
x' = - 4
x" = 4

d) 
5x² - 3x = 0
x (5x - 3 ) = 0
x = 0
5x - 3 = 0 ⇒ 5x = 3 ⇒ x = 3/5 ⇒ x = 0,6
x' = 0
x" = 0,6