Question

Resolva as equações do 2º grau incompletas a seguir:
a) x²-2x = 0
b) 3X²-27 = 0
c) 2x² = 0
d) 5x² + 9x= 0​

Answer 1

a) x² - 2x = 0

x² - 2x ± 0

∆ = 4 - 4 . 1 . 0

∆ = 4 - 0

∆ = 4

$\frac{x = 2 + - 2}{2}$

$x1 = 2 \\ \\ x2 = 0$

b) 3x² - 27 = 0

3x² - 27 ± 0

∆ = 729 - 4 . 3 . 0

∆ = 729

$\frac{x = 27 + - 27}{2}$

$x1 = 27 \\ \\ x2 = 0$

c) 2x² = 0

x² = 0

x = 0

d) 5x² + 9x = 0

5x² + 9x ± 0

∆ = 81 - 4 . 5 . 0

∆ = 81

$\frac{x = - 9 + - 9}{2}$

$x1 = 0 \\ \\ x2 = - 9$