Question

Calcule as raizes da equação
a) 5ײ-20=0

b) 7ײ-21=0

c) 2ײ+5×=0

d) -ײ+4×=0

Answer 1

Olá!!!

Resolução!!!

a)

5x² - 20 = 0
5x² = 20
x² = 20/5
x² = 4
x = ± √4
x = ± 2
x' = + 2
x" = - 2

S = { - 2, 2 }

b)

7x² - 21 = 0
7x² = 21
x² = 21/7
x² = 3
x = ± √3
x' = + √3
x" = - √3

S = { - √3, √3 }


c)

2x² + 5x = 0
x • ( 2x + 5 ) = 0
x' = 0
2x + 5 = 0
2x = - 5
x" = - 5/2

S = { - 5/2 , 0 }

d)

- x + 4x = 0 • ( - 1 )
x² - 4x = 0
x • ( x - 4 ) = 0
x' = 0
x - 4 = 0
x" = 4

S = { 0, 4 }

Espero ter ajudado!!

Answer 2

a)
5ײ - 20=0
5x^2 = 20
x^2 = 20/5
x^2 = 4
x = √4
x = +/- 2

R.: x' = 2; x " = - 2

b)
7ײ-21 = 0
7x^2= 21
x^2 = 21/7
x^2 = 3
x = +/- √3

R.: (+√3; - √3)

c)
2ײ + 5× =0
x.(2x + 5) = 0
x = 0
2x+5 = 0
2x = - 5
x = - 5/2

R.:
x = 0; x = - 5/2


d) -ײ + 4× = 0
x.(-x +4) = 0
x = 0;
- x + 4 = 0
4 = x
x = 4

R.: (0,4)