Question

Resolva as equaçoes do 2 grau incompletas
A] x² - 36 =0

B] 75x² - 3 = 0

C] 2x² - 800 = 0

D] 800x² - 2x =0

Answer 1

$A) x^{2} -36=0\to \\\\ x^{2} =36\to \\\\ x=\pm \sqrt{36} \to\\\\ x=\pm 6\\\\\\ S= \left \{-6;6 \left \}$





$B) 75 x^{2} -3=0\to \\\\ 75 x^{2} =3\to \\\\ x^{2} = \frac{3}{75} \to\\\\ x^{2} = \frac{1}{25} \to\\\\ x=\pm \sqrt{ \frac{1}{25} } \to \\\\ x=\pm \frac{1}{5} \\\\\\S= \left \{-\frac{1 }{5};\frac{1 }{5} \left \}$





$C) 2 x^{2} -800=0\to \\\\ 2 x^{2} =800\to\\\\ x^{2} = \frac{800}{2} \to\\\\ x^{2} =400\to\\\\ x=\pm \sqrt{400} \to \\\\ x=\pm 20\\\\\\ S= \left \{-20;20 \left \}$





$D) 800 x^{2} -2x=0\to \\\\\\ x(800x-2)=0\to \\\\\\ x=0\\\\ 800x-2=0\to 800x=2\to x= \frac{2}{800} \to x= \frac{1}{400} \\\\\\\\S= \left \{0;\frac{1 }{400} \left \}$