Question

1) Calcule as raízes de cada equação:
a) x² - 81 = 0
b) x² - 49 = 0
c) 2x² - 200 = 0

Answer 1

Oie, Td Bom?!

a)

$x {}^{2} - 81 = 0$

$x {}^{2} = 81$

$x = ± \sqrt{81}$

$x = ±9$

$S = \left \{ - 9 \: , \: 9 \right \}$

b)

$x {}^{2} - 49 = 0$

$x {}^{2} = 49$

$x = ± \sqrt{49}$

$x = ± 7$

$S = \left \{ - 7 \: , \: 7 \right \}$

c)

$2x {}^{2} - 200 = 0$

$x {}^{2} - 100 = 0$

$x {}^{2} = 100$

$x = ± \sqrt{100}$

$x = ±10$

$S = \left \{ - 10 \: ,\: 10\right \}$

Att. Makaveli1996