Question

Calcule as raízes das equações abaixo.
a) y = – 5x2 + 5.120 b) y = – 8x2 – 72x

Answer 1

a)

$y = - 5x {}^{2} + 5 \: 120$

$0 = - 5x {}^{2} + 5 \: 120$

$5x {}^{2} = 5 \: 120$

$x {}^{2} = \frac{5 \: 120}{5}$

$x {}^{2} = 1 \: 024$

$x = ± \sqrt{1 \: 024}$

$\boxed{x =±32 }$

$\boxed{S = \left \{ - 32\: , \:32\right \}}$

b)

$y = - 8x {}^{2} - 72x$

$0 = - 8x {}^{2} - 72x$

$- 8x {}^{2} - 72x = 0$

$- 8x \: . \: (x + 9) = 0$

$x \: . \: (x + 9) = 0$

$\boxed{x = 0}$

$x + 9 = 0⟶\boxed{x = - 9}$

$\boxed{S = \left \{ - 9\: , \:0\right \}}$

Att. NLE Top Shotta

Answer 2

Explicação passo-a-passo:

-5x²+5.120=0

-5x²=-5.120

x²= -5.120/-5

x²=1.024

$x = ( + ou - ) \sqrt{1.024}$

$x = + 32 \: \: e \: \: - 32$

$b) - 8x {}^{2} - 72x = 0$

$- 8x.(x + 9) = 0$

$x = 0$

$x + 9 = 0 \\ x = - 9$