Question

b)5x² - 3x = 0
c) x² + x = 0
d) 7x² - x = 0
e) -4x² + 28x = 0
f)-15x² - 5x = 0
me ajudem!!!

Answer 1

Olá,

b)

5x²-3x = 0
x·(5x-3) = 0

x = 0 

ou 

5x-3 = 0
5x = 3
x = 3/5

Resposta:

x = 0 ou x = 3/5

c)

x²+x = 0
x·(x+1) = 0

x = 0

ou 

x+1 = 0
x = -1

Resposta:

x = 0 ou x = -1

d)

7x²-x = 0
x·(7x-1) = 0

x = 0

ou 

7x-1 = 0
7x = 1
x = 1/7

Resposta:

x = 0 ou x = 1/7

e)

-4x²+28x = 0
-4x·(x-7) = 0

-4x = 0
x = 0/-4
x = 0

ou

x-7 = 0
x = 7

Resposta:

x = 0 ou x = 7

f)

-15x²-5x = 0
-5x·(3x+1) = 0

-5x = 0
x = 0/-5
x = 0

ou 

3x+1 = 0
3x = -1
x = -1/3

Resposta:

x = 0 ou x = -1/3