Question

1) Resolva as seguintes equações do 2º grau, sendo U=R:
a) x² – 7x = 0
f) x² + x = 0
b) x² + 5x = 0
g) 7x - x = 0
c) 4x² – 9x=0
h) 2x = 7x
d) 3x² + 5x = 0
i) 2x² = 8x
e) 4x² - 12x = 0
j) 7x² = - 14x​

Answer 1

Resposta:

a) x'=0 e x"= 7

b) x'=0 e x"= -5

c) x'=0 e x"= -9/4

d) x'=0 e x"= -5/3

e) x'=0 e x"= 3

f) x'=0 e x"= -1

g) x'=0 e x"= -1/7

h) x'=0 e x"= 7/2

i) x'=0 e x"= 6

j) x'= 0 e x"= 7

Explicação passo-a-passo:

a) x²-7x =0

x(x-7) = 0

x'=0 x-7 =0

x" =7

b) x²+5x =0

x(x+5) =0

x'= 0 x+5 =0

x"= -5

c) 4x²-9x =0

x(4x-9) =0

x'=0 4x+9=0

4x = -9

x"= -9/4

d) 3x²+5x =0

x(3x+5) =0

x'=0 3x+5 =0

3x = -5

x"= -5/3

e) 4x²-12x =0

4x(x-3) =0

4x=0 x-3=0

x=0/4 x"=3

x'=0

f) x²+x =0

x(x+1) =0

x'=0 x+1 =0

x"= -1

g) 7x²+x =0

x(7x+1) =0

x'=0 7x+1 =0

7x= -1

x"= -1/7

h) 2x²=7x

2x² -7x =0

x(2x-7) =0

x'=0 2x-7=0

2x= 7

x"= 7/2

i) 2x²-12x=0

2x(x-6) =0

2x =0 x-6 =0

x =0/2 x"= 6

x'= 0

j) 7x²=14x

7x² -14x=0

7x(x-7)=0

7x=0 x-7=0

x=0/7 x= 7

x'=0