Question

11-resolva as seguintes equações incompletas do 2 grau:
a)x²+5x=0
b)3x²-6x=0
c)x²+7x=0
d)4x²-12x=0
e)5x²-15x=0
f)x²-8x=0
g)2x²+6x=0

Answer 1

11-resolva as seguintes equações incompletas do 2 grau:
a)x²+5x=0 
x(x + 5) = 0

x = 0
e
(x + 5) = 0
x + 5 = 0
x = - 5
assim
x' = 0
x" = - 5

b)3x²-6x=0 
3x(x - 2) = 0

3x = 0
x = 0/3
x = 0
e
(x - 2) = 0
x - 2 = 0
x = + 2

assim
x' = 0
x" = 2
 
c)x²+7x=0
x(x + 7) = 0
x = 0
(x + 7) = 0
x + 7 = 0
x = - 7

assim
x' = 0
x = - 7

d)4x²-12x=0
4x(x - 3) = 0
4x = 0
x = 0/4
x = 0
e
(x - 3) = 0
x - 3 =0
x = + 3

x' = 0
x" = 3

e)5x²-15x=0
5x(x -3) =0
5x = 0
x = 0/5
x = 0
e
(x - 3) = 0
x - 3 = 0
x = + 3

x' = 0
x" = 3


f)x²-8x=0
x(x - 8) = 0
x = 0
(x - 8) = 0
x - 8 = 0
x = + 8

x' = 0
X' = 8


g)2x²+6x=0
2x(x + 3) = 0
2x = 0
x = 0/2
x = 0

(x + 3) = 0
x + 3 = 0
x = - 3

x' = 0
x" = - 3