Question

1- Dados os números 23,5 x 10³ e 5,3 x 10³,

a) Some-os

b) Subtraia-os


2- Determine a raiz quadrada dos números abaixo:

a) 196 b) 576


3- Resolva as equações incompletas do segundo grau:

a) 5x2 – 80 = 0 b) x

2 – 144 = 0


4- Resolva as equações incompletas do segundo grau:

a) 9x² – 3x = 0 b)x² + 8x = 0

alguem me ajuda nao estou entendendo, Por favor ​

Answer 1

Explicação passo-a-passo:

1.

a)

$\sf 23,5\times10^3+5,3\times10^3=(23,5+5,3)\times10^3$

$\sf 23,5\times10^3+5,3\times10^3=28,8\times10^3$

b)

$\sf 23,5\times10^3-5,3\times10^3=(23,5-5,3)\times10^3$

$\sf 23,5\times10^3-5,3\times10^3=18,2\times10^3$

2.

a) 196

196 | 2

98 | 2

49 | 7

7 | 7

1

196 = 2² x 7²

$\sf \sqrt{196}=\sqrt{2^2\cdot7^2}$

$\sf \sqrt{196}=2\cdot7$

$\sf \sqrt{196}=14$

b) 576

576 | 2

288 | 2

144 | 2

72 | 2

36 | 2

18 | 2

9 | 3

3 | 3

1

576 = 2⁶ x 3²

$\sf \sqrt{576}=\sqrt{2^6\cdot3^2}$

$\sf \sqrt{576}=2^3\cdot3$

$\sf \sqrt{576}=8\cdot3$

$\sf \sqrt{576}=24$

3.

a) $\sf 5x^2-80=0$

$\sf 5x^2=80$

$\sf x^2=\dfrac{80}{5}$

$\sf x^2=16$

$\sf x=\pm\sqrt{16}$

$\sf x'=4$

$\sf x"=-4$

$\sf S=\{-4,4\}$

b) $\sf x^2-144=0$

$\sf x^2=144$

$\sf x=\pm\sqrt{144}$

$\sf x'=-12$

$\sf x"=12$

$\sf S=\{-12,12\}$

4.

a) $\sf 9x^2-3x=0$

$\sf 3x\cdot(3x-1)=0$

$\sf 3x=0~\longrightarrow~x=\dfrac{0}{3}~\longrightarrow~x'=0$

$\sf 3x-1=0~\longrightarrow~3x=1~\longrightarrow~x"=\dfrac{1}{3}$

$\sf S=\left\{0,\dfrac{1}{3}\right\}$

b) $\sf x^2+8x=0$

$\sf x\cdot(x+8)=0$

$\sf x'=0$

$\sf x+8=0~\longrightarrow~x"=-8$

$\sf S=\{-8,0\}$