Question

Determine as raizes reais das equaçoes incompletas
a) x²-5x=0
b)-x²+12x=0
c)5x²+x=0
d)x²-9x=0
e)x²-0=0
f)25x²-1=0
g)x²-64=0
h)x²+16=0
i)-7x²+28=0

Answer 1

Determine as raizes reais das equaçoes incompletas
a) x²-5x=0

x² - 5x = 0
x(x - 5) = 0

x = 0
e
(x - 5) = 0
x - 5 = 0
x = + 5

assim
x' = 0
x" = 5
 
b)-x²+12x=0

- x² + 12 = 0
x(- x + 12) = 0

x = 0

(- x + 12) = 0
- x + 12 = 0
- x = - 12
x = - (-12)
x = + 12

x' = 0
x" = 12

c)5x²+x=0

5x² + x = 0
x(5x +1) = 0

x = 0

(5x + 1) = 0
5x + 1 = 0
5x = - 1
x = - 1/5

x' = 0
x" = -1/5  

d)x²-9x=0
x² - 9x = 0
x(x - 9) = 0

x = 0
(x - 9) = 0
x - 9 = 0
x = + 9

a' = 0
x" = 9

e)x²-0=0

x² - 0 = 0
x² = +0
x = √0
x = 0
x' e x" = 0
 
f)25x²-1=0

25x² - 1 = 0
25x² = 1
x² = 1/25    
x = + - √1/25
x = + - √1/√25
x = + - 1/5

x' = - 1/5
x" = 1/5

g)x²-64=0

x² - 64 = 0
x² = + 64
x = + - √64
x = + - 8

x' = - 8
x" = 8
 
h)x²+16=0

x² + 16 = 0
x² = - 16
x = + - √-16   ( NÃO existe raiz REAL)
porque????
(RAIZ quadrda com Número NEGATIVO)


i)-7x²+28=0

- 7x² + 28 = 0
- 7x² = - 28
x² = - 28/-7
x² = +28/7
x² = 4
x = + - √4
x = + - 2

x' = - 2
x" = 2