Question

determine,os valores reais que são soluçoes das equaçoes: a) x²+12x=0
b) 6x² - 5x = 0
c) 3x²- 60x+225=0

Answer 1

a)x² + 12 x = 0
x(x + 12 ) = 0
x = 0
x + 12 = 0
x = -12
S = {0 , -12}

b)6 x² - 5 x = 0
x(6 x - 5 ) = 0
x = 0
6 x - 5 = 0
6 x = 0 + 5
6 x = 5
x = 5/6
A = {0 , 5/6}

c)3 x² - 60 x + 225 = 0
Δ = b² - 4.a.c
Δ = (-60)² - 4.3.225
Δ = 3600 - 2700
Δ = 900 ⇒√900 = 30
x = -b + ou - 30/2.3
x´= -(-60) + 30/6 ⇒60 + 30 / 6 = 90/6 = 15
x`` = 60 - 30 / 6 ⇒30 / 6 = 5

S = {5 , 15}