Question

alguém pra me ajuda????​

Answer 1

$a)\\5x^2-25x=0\\\\=5xx-25x\\\\=5xx-5\cdot \:5x\\\\=5x\left(x-5\right)\\\\5x\left(x-5\right)=0\\\\x=0\quad \mathrm{or}\quad \:x-5=0\\\\x-5=0\\\\x-5+5=0+5\\\\x=5\\\\x=0,\:x=5$                              $b)\\x^2-7x=0\\\\x^2-7x\\\\=xx-7x\\\\=x\left(x-7\right)\\\\x\left(x-7\right)=0\\\\x=0\quad \mathrm{or}\quad \:x-7=0\\\\x-7=0\\\\x-7+7=0+7\\\\x=7\\\\x=0,\:x=7$

$c)\\2x^2-128=0\\\\2x^2-128+128=0+128\\\\2x^2=128\\\\\frac{2x^2}{2}=\frac{128}{2}\\\\x^2=64\\\\x=\sqrt{64},\:x=-\sqrt{64}\\\\=\sqrt{8^2}\\\\\sqrt{8^2}=8\\\\=8\\=\sqrt{8^2}\\\\\sqrt{8^2}=8\\\\=-8\\\\x=8,\:x=-8$        $d)\\10x^2-250=0\\\\10x^2-250+250=0+250\\\\10x^2=250\\\\\frac{10x^2}{10}=\frac{250}{10}\\\\x^2=25\\\\x=\sqrt{25},\:x=-\sqrt{25}\\\\=\sqrt{5^2}\\\\\sqrt{5^2}=5\\\\=5\\\\-\sqrt{25}\\\\\sqrt{5^2}=5\\=-5\\\\x=5,\:x=-5$

Answer 2

As respostas são respectivamente:

a) S = {0,5}       b) s = {0,7}      c) S = {±8}        d) S = {±5}    

Solução de Equações de 2º Grau

Resolve-se usando a regra de fatoração: fator comum em evidencia.

a) 5x² - 25x = 0

   5x(x-5)=0

   x' = 0

   x = 5

b) x² - 7x = 0

   x(x-7)=0

   x'=0

   x'' = 7

c) 2x² - 128 = 0

   2x² = 128

     x² = 54

     x² = ± $\sqrt{64}$

     x = ± 8

d) 10x² - 250 = 0

    10x² = 250

     x² = 250 : 10

     x² = 25

     x = ± $\sqrt{25}$

     x = ± 5

Veja mais nas tarefas:

https://brainly.com.br/tarefa/32340555

https://brainly.com.br/tarefa/32139735

https://brainly.com.br/tarefa/2370059

Confira o link de Soluções de Livros Didáticos do Brainly:

brainly.com.br/livrosdidaticos