Question

ME AJUDA PFV!Resolva as equações do 2º grau incompletas:
a) 4x² - 9 = 0
b) X² - 81 = 0
c) x² - 7x = 0
d) x² + 5x = 0
e) 2x² - 90 = 8

Answer 1

Resposta:

a) 4x² - 9 = 0     S = (+ $\sqrt{\frac{9}{4} }$, - $\sqrt{\frac{9}{4} }$)

x²= 9/4

x = $\sqrt{\frac{9}{4} }$

b) X² - 81 = 0       S = ( -9, +9)

x = $\sqrt{81}$

x = 9

c) x² - 7x = 0    S= ( 0, 7)

x(1x -7) = 0

x= 0

1x - 7 = 0

x= 7

d) x² + 5x = 0    S = ( 0, -5)

x(1x + 5) = 0

x= 0

1x +5 = 0

x= -5

e) 2x² - 90 = 8    S= ( +7, -7)

x² = 98/2

x= $\sqrt{49}$

x = 7