Question

resolva as equações do segundo grau:

a)
$4 {x}^{2} - 36 = 0$
b)
$7 {x}^{2} - 21 = 0$
c)
${x}^{2} + 9 = 0$
d)
${x}^{2} - 49 = 0$
e)
$5 {x}^{2} - 20 = 0$

Answer 1

a. 4x^2 - 36 = 0
4x^2 = 36
x^2 = 36/4
x = √9 = 3

b. 7x^2 - 21 = 0
7x^2 = 21
x^2 = 21/7
x = √3

c. x^2 + 9 = 0
x^2 = -9
x = √-9 = 3i

d. x^2 - 49 = 0
x^2 = 49
x = √49 = 7

e. 5x^2 - 20 = 0
5x^2 = 20
x^2 = 20/5
x = √4 = 2